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Archives 2010s >> 2012 Forecast Lounge

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cieldumort
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Hurricane Isaac Forecast Lounge
      #93210 - Fri Aug 17 2012 02:38 AM

A new Invest has just been tagged for the large tropical wave in the extreme eastern Atlantic.

Invest 94L, large, broad and elongated, is presently located roughly in the vicinity of 11N 20W at 2:30 AM EDT Aug 17. Pressure is estimated to be 1010mb, with maximum sustained winds of about 25 MPH. Movement is currently to the west at 15-20 MPH.

This is where to put long range best guesses on intensity and forecast track. Long range model output discussions are also appropriate here.

Model support on Invest 94L so far is pretty strong, with several of the better models whipping up a strong tropical cyclone out of it in the central Atlantic by the middle of next week. As early model runs often tend to be the least reliable, it remains to be seen if they verify, but right now there does not appear to be much working against 94L over the next 4-7 days.

Edited by cieldumort (Tue Aug 28 2012 04:42 PM)


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Ed DunhamAdministrator
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Re: Invest 94L Forecast Lounge [Re: cieldumort]
      #93215 - Fri Aug 17 2012 12:56 PM

As noted above some of the models are aggressive in developing Invest 94L - most notably the DSHIP and GFS and to a lesser extent the ECMWF - with a significant system in the central Atlantic in about five days. I've noted that each succeeding run of the GFS moves the system a little more westward before the eventual turn to the north through a developing weakness in the Atlantic ridge.
ED


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WeatherNut
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Re: Invest 94L Forecast Lounge [Re: Ed Dunham]
      #93220 - Sat Aug 18 2012 11:53 AM

Looking at some of the models, this is starting to look like a possible East Coast threat. They are showing 2 systems developing out of the broad monsoon trough. I'm not sure I buy that and it would suggest a recurve. If only 1 system that makes me think a more westward track longer with a possible threat to the islands in 5 days...have to see how this plays out in the next couple of days. The models, however, have been trending west

--------------------
Born into Cleo (64)...been stuck on em ever since


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weathernet
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Re: Invest 94L Forecast Lounge [Re: cieldumort]
      #93221 - Sat Aug 18 2012 12:55 PM

Those who continue to access this site for sound & reasonable information need heed the future development of 94L. All those from the Greater Antilles, especially the Leewards and Puerto Rico, need to really heed 94L - evenutally to become Hurricane Isaac. Not only am I confident that Isaac will prove to be one of the "highlights" of the 2012 Atlantic Season, but anticipate a very significant threat from Florida to North Carolina, if Isaac impacts or moves just north of Puerto Rico. On the other hand, if Isaac remain further south I would be very concerned about a major impact to points along the N. Gulf Coast region. Folks, this large envelope system should not have any of the recent "dry air intrusion issues" and this appearant large system should be able to draw on a larger scale inflow of rich moisture from its south. Westerly upper level wind shear should not be a factor, other than a possible near term displacement of a COC simply caused by its own faster westward motion. Upper level conditions should not likely inhibit Isaac from eventually attaining "major hurricane status. While no set of circumstances are set in stone, I see it as very unlikely that this system will simply move well north of the Islands.

Edited by Ed Dunham (Sun Aug 19 2012 11:47 PM)


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Mozart
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Re: Invest 94L Forecast Lounge [Re: weathernet]
      #93222 - Sat Aug 18 2012 03:45 PM

Interesting difference in the models between the NGP and GFS if I'm reading this right. (I'm an amateur at best.) The NGP has 94L starting a recurve to the north before it gets too far west. The GFS has it in the Caribbean in 5 days and appears to be on a path for the Gulf of Mexico.

--------------------
Agnes - 1972, David - 1979, Bob - 1985
Hugo - 1989
TS Jerry - 1995 (14 inches of rain in 12 hours)
Hurricane Ivan - 2004


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doug
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Re: Invest 94L Forecast Lounge [Re: Mozart]
      #93223 - Sat Aug 18 2012 05:35 PM

GFS has the better track record ( no pun intended)...it is one of the most highly regarded model composites

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doug


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MichaelA
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Re: Invest 94L Forecast Lounge [Re: doug]
      #93225 - Sat Aug 18 2012 06:10 PM

Statistically, storms forming that far East usually re-curve well before they reach the Caribbean. If 94L were to remain an open wave (which it doesn't appear to be doing) and became a tropical cyclone closer to 15ºN; 45 - 50ºW, then I'd be more concerned about a Caribbean/GoM event.

--------------------
Michael

WU PWS

2020 “guess:” 15/8/3
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Mozart
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Re: Invest 94L Forecast Lounge [Re: MichaelA]
      #93233 - Sun Aug 19 2012 01:08 PM

Big change in the models today from yesterday. Long term GFS has 94L going over Jamaica and GFDL has it heading into the Bahamas. Neither one seems to develop it very much though. Hoping it doesn't develop too much and cause havoc in the Caribbean.

--------------------
Agnes - 1972, David - 1979, Bob - 1985
Hugo - 1989
TS Jerry - 1995 (14 inches of rain in 12 hours)
Hurricane Ivan - 2004


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WeatherNut
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Re: Invest 94L Forecast Lounge [Re: Mozart]
      #93236 - Sun Aug 19 2012 03:40 PM

The 2p models are coming in even farther south...and the SHIPS intensity forecast still predicts a 108kt hurricane in 120hrs. Thats a long way out, but the models have not been so aggressive strenthening systems thus far this season...so cation is advised with this system.
Another point to make though...I am seeing some rotation in the system out front of 94L which was forecast by some of the global models previously approx 11n 47w (again approx). If this tries to develope it could put a wrench into the forecast...it also shows conditions improving ahead for 94L

--------------------
Born into Cleo (64)...been stuck on em ever since

Edited by WeatherNut (Sun Aug 19 2012 03:45 PM)


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Joeyfl
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93237 - Sun Aug 19 2012 05:37 PM

94L looking a little better organized from a circulation stand point and banding features becoming more evident. However deep convection is lacking based on satellite and water vapor shows plenty of dry air to the north and west of 94l and is helping to keep it in check. However Dvorak numbers are 1.5 from both TAFB and SAB which is up from this mornings numbers 1.0. Would not be surprised to see this as depression later tonight or early tomorrow morning. A steady Westerly movement into the northwest Caribbean looks good for now and beyond that plenty to discuss with ridge hold strong enough to north and keep it moving West/WNW or will there be a turn northwest. I like the GFS up to this point.

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Buckeye
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Re: Invest 94L Forecast Lounge [Re: Mozart]
      #93238 - Sun Aug 19 2012 06:15 PM

Quote:

Big change in the models today from yesterday. Long term GFS has 94L going over Jamaica and GFDL has it heading into the Bahamas. Neither one seems to develop it very much though. Hoping it doesn't develop too much and cause havoc in the Caribbean.





After watching the many different model histories over the years, I am convinced that the people at GFDL have it in for Florida for some reason. If you have tracked the models for any significant storm over the past 10-15 years, you will have to agree that GFDL consistently, and inexplicably, tracks every time towards Florida. I say inexplicably, because frequently, if not the vast majority of the time, GFDL's track model is noticeably different from most, if not all, of the other model forecast tracks. I have since wondered what the people in Princeton have against us down here in Florida.

Edited to include referenced quote for context.


Edited by cieldumort (Sun Aug 19 2012 07:18 PM)


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Urbanoia
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Re: Invest 94L Forecast Lounge [Re: Buckeye]
      #93241 - Mon Aug 20 2012 09:16 AM

possibly hyper-active algorithms for the effects of the Gulf Stream? It could explain the models turning north in long range forecasts if the storms get north of the Leewards. I know the surf has been pushing moderate to hard in Cocoa Beach from the SE all summer, more than I remember in past years. Though a warming planet should ease the stream, I haven't seen it yet here. And our thermocline hit the surf more or less on target this weekend for the first time all summer, crabs standing around on the beach at noon is usually a pretty good sign the water just got frigid. Just in time for a small bit of cold water moderation as the long-range GFS turn of 94L turns towards us (again!) and another unneeded gassing of the RV for escape. Been since 2006 when we got hit three times in three weeks and my insurance is still going up and the batteries are still dead in the RV. But I wouldn't live anywhere else, especially in NJ.

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Beach
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Re: Invest 94L Forecast Lounge [Re: cieldumort]
      #93242 - Mon Aug 20 2012 09:48 AM Attachment (556 downloads)

The GFS model certainly has been acid tested over the years. Today they have 94 coming over the glades and right up and over lake Okeechobe. It's already been proven several years ago when a week hurricane picked up steam crossing over this HUGE, HOT, body of water.

My guess is that next week, there will be a lot of knashing about what Helene will do. ... Thanks for the correction.
(Actually it was Frances that came ashore near Stuart.)

Edited by Beach (Mon Aug 20 2012 02:25 PM)


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LoisCane
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Re: Invest 94L Forecast Lounge [Re: Beach]
      #93243 - Mon Aug 20 2012 11:39 AM

The models have run several scenarios... many ignored like the out to sea forecasts which are pretty much out to sea. Had Isaac formed and been strong... he might have taken that track up the Atlantic... but the "good news" of Isaac not being Isaac may be "BAD NEWS" down the road as he gets further west every 12 hours and the models respond in each new run and he now becomes your classic CV storm where he "can" go up over the islands towards Florida and the GOM or the East Coast of the US ...OR........he can go through the islands, stay south of a tango with Haiti and come up under Cuba and aim towards either Tampa or Miami and the rest of the East Coast of Florida.

So... this concept of him looking bad is good news should be thrown out a window as weak and steady as he moves towards warmer water with what seems good bone structure that would favor big, giant bands circling around a developed center is BAD NEWS actually.... not bad as in "hype" its just bad as in reality bites.

You have to look LONG TERM at a LONG TRACKER. Early strong storms curve WNW and NW. Early strong storms catch the ULL or a doorway away from a landfall... slow, steady storms like this one keep getting further west, further south and the BIG difference between this one and the last few is.......FALL has set in early. Fronts are now moving south... there is a bit less dust, warmer water... a frontal boundary that pushed through FL/GA and then backs up and becomes a stationary front could be more of a problem. Just a different set of factors with this storm (and the ones behind it) than what happened to Ernesto/Hector.

So... keep watching. But, yeah.... I keep seeing variations on Cleo and Donna and that would imply Cuba gets this before Florida...if Florida gets it. (How much do we trust the GFS this far out???) But that ole Seminole Wind may blow real strong if Isaac forms and follows the GFS.

And, if Cuba gets it vs Haiti... there is less of a chance of it falling apart and of course it depends if Cuba gets it where it crosses Cuba... up over the islands would imply a much stronger storm but the GFS is not showing that scenario this morning...

Keep watching...

--------------------
http://hurricaneharbor.blogspot.com/


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ftlaudbob
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93245 - Mon Aug 20 2012 12:19 PM

Very good post Lois,I agree.This one has my attention.I do not believe this one will be a fish spinner,and the conditions out in front of the system are conducive for slow development.If it does affect the U.S. (And I believe it will) We are looking at about a week.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: ftlaudbob]
      #93248 - Mon Aug 20 2012 03:42 PM

Today's 12Z EMCWF (Euro) model run puts a storm from 94L through South Florida, up the east coast and then west across Florida, Tues-Thursday (28-30th) of next week.

These model runs are a bit too far out/too weak to believe right now, but if the trends hold out it will be something those in the Gulf and Florida will want to watch into next week.


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CoconutCandy
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93253 - Mon Aug 20 2012 06:30 PM

The large, sprawling Tropical Disturbance we've all been following these past few days now appears much better organized and is quickly consolidating into a Tropical Depression.

Although certainly large and impressive looking (for a disturbance), 94L hasn't been particularly organized quite yet, nor has the convection been especially deep, being seemingly confined, thus far, to a linear banding feature stretching in an east / west line south of what appears to have been several competing low level circulation centers.

Well, all that has certainly changed today, with the disturbance taking on a much more symmetrical appearance, and a dramatic increase in convective organization, especially in the SE quadrant, as clearly portrayed in this animated visible satellite imagery.



You can easily see the massive flare-up of thunderstorms in the SE quadrant, as well as a general increase in shower bands forming in all quadrants, with thunderstorms also beginning to pop in curved cumulus streets in the NW quadrant.

Also of note in this animated imagery is a pretty decent outflow channel developing in the southern semicircle, quickly whisking away the cirrus debris from the underlying convection and shunting it off to the SW.

Interestingly, deep convection near and over the tight spiral of the currently exposed low level circulation have been paltry, at best, with only a few, transient, moderate storms intermittently flaring up.

But especially apparent is the Overall Increase in Organization of the Disturbance and the Rapidly Developing Symmetry of the system in general, as shown from the beginning of the loop to it's last frame, late in the day (local time), which also accentuates the blowup of thunderstorms to the SE, and their sharply increasing curvature during the time frame depicted.

All in all, I'd have to say that, after loosely languishing for a few days, 94L is quickly "getting it's act together", and is looking more and more impressive by the hour.

And, now that the nascent cyclone is entering the overnight convective maximum cycle, when thunderstorms usually attain their greatest proportions and coldest cloud tops, I'd expect to see a massive flare-up of "bursting" convection, with cloud tops of -70 to -80 degrees and colder, building closer and closer to the LLCC.

And when THAT happens, it imparts a MASSIVE quantity of energy to the developing cyclone, as enormous amounts of heat is released into the atmosphere (the release of latent heat of condensation), which, in turn, causes the gradual development of a true warm core, lowering surface pressures, stiffening the low level winds by several notches, causing even more surrounding warm air of very high CAPE (convective available potential energy) to continue to spiral in towards the center, initiating a positive feedback mechanism that continually escalates the entire process, and Viola !! Cyclogenesis.

Like many of you, I've got 'a feeling in my bones' that this just might be a storm we'll all remember for some time to come. Time will tell, but with each model run, and the track shifting progressively further west before a turn to the north, this looks to be a storm the US needs to very much keep appraised of.

One last thing: I find the name "Isaac" to be very telling. Can anyone guess WHY ?? (Hint: Something that happened well over a century ago.)

Edited by Ed Dunham (Mon Aug 20 2012 11:47 PM)


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LoisCane
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Re: Invest 94L Forecast Lounge [Re: CoconutCandy]
      #93254 - Mon Aug 20 2012 07:25 PM

Galveston does not appreciate your sense of humor. Yeah Isaac could be some storm once it develops. Should hit warmer water soon.

The dust is really doing a job on it...

http://tropic.ssec.wisc.edu/real-time/sal/splitE/movies/splitE5.html

If it stays low intensity wise... I don't see the northerly tracks really working out.

Another issue I have is that the GFS only really intensifies the storm as it is hitting Cuba and traversing Cuba, which doesn't seem logical. I don't believe Cuba would hurt a storm that much as I blogged earlier today...but what I don't think is logical is that it intensifies over land.

A missing piece of the puzzle.

I do think it's pretty clear fronts are moving down and will begin tugging storms away from the Yucatan or bust scenario of the previous storms.

Edited by Ed Dunham (Mon Aug 20 2012 11:48 PM)


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ftlaudbob
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93255 - Mon Aug 20 2012 07:44 PM

Looks to me like it is going to win the fight with the dry air,in the last frame or two it seems there is less dry air (dust) in front of it.

Edited by Ed Dunham (Mon Aug 20 2012 11:49 PM)


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ftlaudbob
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Re: Invest 94L Forecast Lounge [Re: ftlaudbob]
      #93256 - Mon Aug 20 2012 07:59 PM

NHC has upped 94L to 90% chance in the next 48 hours.

Edited by Ed Dunham (Mon Aug 20 2012 11:50 PM)


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LoisCane
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Re: Invest 94L Forecast Lounge [Re: ftlaudbob]
      #93257 - Mon Aug 20 2012 08:26 PM

less and less dry air and warmer water ... as well

Edited by Ed Dunham (Mon Aug 20 2012 11:51 PM)


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Joeyfl
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93258 - Mon Aug 20 2012 08:39 PM

94L has not changed much with respect to convection however the LLC is well defined and think its just a matter of 24 hrs or so before we see a gradual intensification on this system. Deeper moisture to the east and south should gradually be pulled more into the center however it will likely battle dry air while over the Atlantic. As far as the future track of this system the GFS still looks good to be and model guidance at least the so called more reliable models are all fairly close. Beyond 5 days is hard to tell but a threat the U.S is moderate I would say especially the Southeast U.S...

Edited by Ed Dunham (Mon Aug 20 2012 11:52 PM)


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CoconutCandy
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Re: Invest 94L Forecast Lounge [Re: Joeyfl]
      #93259 - Mon Aug 20 2012 09:27 PM

Just a quick follow up for now: As I had speculated earlier, the convective and organizational trends established during the daylight hours (see animated visible satellite loop, previous post) have continued unabated during the diurnal convective max cycle, with the convective banding features so clearly evident previously in the SE quadrant, have continued to intensify and also increased in aerial extent, all the while pulling in closer and closer to the low lever center of circulation.

Moreover, thunderstorms have begun initiating closer what was previously an exposed LLCC, especially immediately to the W and SW of the center, as clearly portrayed in the following animation.



NRL has lowered the central pressure by a millibar, while bumping up the estimated sustained winds to 30 knots, and the latest NHC Tropical Weather Outlook reveals " ... ANY SIGNIFICANT INCREASE IN THUNDERSTORM ACTIVITY COULD RESULT IN THE FORMATION OF A TROPICAL DEPRESSION TONIGHT OR TOMORROW."

I think we're well on our way to cyclogenesis, and should convection continue to increase overnight, I'd not be at all surprised to see a Depression, or even a named storm, by the break of day, local basin time.

(PS: Yes Lois, you are spot on: I was referring to Isaac Cline, the Meteorologist at Galveston in 1900, when that city was utterly destroyed, with the loss of 6,000+ lives, including his wife and many he knew. I'll be making a separate post in the "Hurricane Ask / Tell" Forum soon, to share with those who may not know the story of Isaac Cline and the harrowing ordeal he went through, greatly underestimating the impact of the US's deadliest hurricane.)

Edited by Ed Dunham (Mon Aug 20 2012 11:52 PM)


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Mozart
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Re: Invest 94L Forecast Lounge [Re: ftlaudbob]
      #93260 - Mon Aug 20 2012 09:37 PM

94L is really confusing me. It seems to have a distinct center, but little convection in that area. Down to the SE there is moderate convection but tonight it doesn't seem to have any flareup. What concerns me is that if it doesn't gain strength now, the GFS might just be right and the storm makes its way into the Caribbean before starting to gain strength and turning north through Cuba and into Florida.

Edited by Ed Dunham (Mon Aug 20 2012 11:53 PM)


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Joeyfl
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Re: Invest 94L Forecast Lounge [Re: Mozart]
      #93261 - Mon Aug 20 2012 10:13 PM

I would guess that we will probably have a depression by early morning on 94L. While convection near center is minimal right now I think it is slowly getting its act together. Dvorak numbers are only 1.0 right now from both TAFB and SAB, would like to see these in the 1.5/2.0 range. Again it is quite surprising to see the reliable models in such good agreement through through the long term. As this develops and moves into Caribbean the important factor will be its interaction with Hispaniola and eastern mountains of Cuba. If it slides just south z(GFS/ECMWF) of the these islands it could mean a stronger storm/hurricane.

Edited by Ed Dunham (Mon Aug 20 2012 11:54 PM)


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Mozart
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Re: Invest 94L Forecast Lounge [Re: Joeyfl]
      #93262 - Mon Aug 20 2012 10:51 PM

I'm confused about something. Someone in another forum posted the current GFS ensemble. It seems to lean toward a Myrtle Beach/Wilmington landfall while the GFS is still pointing to Florida. Am I just missing something here? Doesn't it seem like the two should be in line with each other?

Anyway, either scenario points towards a strengthening of the storm before it hits land in the US. (Yes, I'm a fan of the GFS. It just seems to have a better handle on these things.) Based on that and the overall computer model outlook, people in the Southeast need to have their eye on this one. I'm not seeing major hurricane as yet in the overall outlook, but it could really cause some problems for people in these areas. Fortunately, I think that few in these areas overlook the potential that these storms could cause based on the recent history. Now is the time to start making preparations with regards to storm necessities, not at the last minute like most will. Not wishcasting, just trying to make the case that everyone needs to keep an eye on this one.

Edited by Ed Dunham (Mon Aug 20 2012 11:47 PM)


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cieldumort
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Re: TD 9 Forecast Lounge [Re: cieldumort]
      #93264 - Tue Aug 21 2012 04:52 AM

Invest 94L has just been upgraded to Tropical Depression Nine. Tropical Storm Watches & Warnings have been issued for much of the eastern Caribbean, and it is likely that Nine will become Isaac today.

Nine's internal structure is very impressive, and now that the cyclone is able to more efficiently chase away dry air, it is possible that it intensifies faster than initially forecast; while such an event could give the Antilles a blow, yet spare the rest of the Caribbean and Florida, this is by no means a guarantee. High pressure to Nine's north is pretty solid, and it is not clear whether enough weakness will exist to allow even a moderate tropical cyclone to veer poleward prior to getting a good deal further west.


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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93267 - Tue Aug 21 2012 08:01 AM

For beyond the Caribbean talk, The forecast track is going to be heavily influence by Hispaniola, if it moves over Dominica/Haiti it will tear the system up leaving rain if it were to make it close to Florida. If it manages to stay south of the island it has a chance to remain more together and a chance to affect Florida mid next week.

Too much up in the air to say anything more than watch it, the latest global GFS does take it over parts of Haiti and Cuba, but also though the spine of Florida. Expect that to change several times.

This storm is in a similar position to Irene from last year, so in reality, if it survives the northern Caribbean islands, those in the US from Florida on up will want to keep track of it. Puerto Rico and the US VI are in the Tropical Storm watch area.



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Ed in Va
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93268 - Tue Aug 21 2012 08:16 AM

Given the expected near Cat 3 strength, I'm expecting the path to move poleward over time. Here's a link to Irene about the same time last year http://outerbanksvoice.com/2012/08/20/first-anniversary-of-the-birth-of-hurricane-irene/

--------------------
Survived Carol and Edna '54 in Maine. Guess this kind of dates me!


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stormtiger
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93270 - Tue Aug 21 2012 09:31 AM

Kudoes to Coconut Candy for some very good forecasting yesterday. Great job, great explanation and great visuals.

Right now it seems to me like the two big factors are the dry air and how much it limits the future Issac in the near term and causes it to stay weaker, and the orientation of the Atlantic ridge and just how far West it extends in the next 3-5 days.

I think the GFS and the European models both have a good handle on this storm, and the key will be whether or not the future Issac stays south of central Cuba or strikes Hispanola or Eastern Cuba. The broad track seems pretty clear, but the devil is in the details.

A front passed through La. early yesterday and it is leaving a weakness for Issac to take north. Right now that path seems to be open towards Florida and specifically the southern tip.


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Joeyfl
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Re: Invest 94L Forecast Lounge [Re: stormtiger]
      #93271 - Tue Aug 21 2012 10:24 AM

It looks as though we could have Issac rather soon Dvorak numbers are 2.0 TAFB and SAB. Satellite presentation looks to be improving some as it moves west at a good clip impacting the islands late tonight and early tomorrow morning. Future track reasoning has changed little since yesterday, agree with NHC track up to this point with their track following closely to GFS which has been rather consistent to this point. Their experimental track through day 7 has this following GFS right up the spine of Florida. I don't think theres any question that there will be a weakness however does it turn up through the western Bahamas, over Florida, or slightly further west (eastern Gulf) is to early to tell. For now I like GFS, of note GFS ensemble members are little more east then yesterday but flip/floping that far out is likely and would expect and much higher confidence in track by end of the work week. I would be on alert in Southern U.S from eastern Gulf to South Carolina.

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WeatherNut
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Re: Invest 94L Forecast Lounge [Re: Ed in Va]
      #93272 - Tue Aug 21 2012 10:59 AM

The new GFS has slipped south of Hispanolia and the European still wants to take it to the central GOM. My biggest concern is that if it misses Haiti there is a huge amount of oceanic heat content in its path and the loop current is especially warm this year. I also have a great concern in there will be a lot of nonresidents in the Tampa Bay region which is one of the most dangerous areas to be in should a strong hurricane come calling. This to me looks like a cone anywhere from New Orleans to Cape Hatteras...but Haiti will be key...if it misses...we are looking at a major hurricane IMO

--------------------
Born into Cleo (64)...been stuck on em ever since


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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93273 - Tue Aug 21 2012 12:23 PM

The 12Z GFS run ( Linked here ) takes it through eastern Cuba, landfalling in the Keys late Monday/Tuesday and again in Southwest Florida going up through the spine along the west coast.

This will probably change again.


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mikethewreck
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93275 - Tue Aug 21 2012 01:43 PM Attachment (476 downloads)

Is anyone else struck by the similarity to the 1964 Cleo track? That storm is my earliest memory, recalling my father doing a no-no and going out during the eye to clear debris in our back yard.

--------------------
Earliest memory Hurricane Cleo!
Went under Hurricane Gloria!


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LoisCane
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Re: Invest 94L Forecast Lounge [Re: mikethewreck]
      #93276 - Tue Aug 21 2012 01:55 PM

I remember Cleo. A very similar track indeed. And, Cleo made a sharp turn. Also same time of year.

http://weather.unisys.com/hurricane/atlantic/1964/CLEO/track.gif

Waiting to hear data from recon...

--------------------
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Robert
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93277 - Tue Aug 21 2012 02:05 PM

The Forward speed has slowed to 18mph from this morning. I have bias on the NOGAPS and a path over or to the north of hispanola and up the back bone of the bahamas. The NOGAPS calls for slowing sooner then later.

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Robert
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93278 - Tue Aug 21 2012 02:29 PM

I was thinking, the NOGAPS slows the storm down considerably then turns north, it also tries to develop another the low to the ne of isaac. could this be 96L behind isaac. I was thinking something like a TS Fay track but further east. Mayby the low the NOGAPS seas is it trying to pull out all the moisture, as in an error. and that isaac instead gets trapped?

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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: Joeyfl]
      #93279 - Tue Aug 21 2012 02:36 PM

The amount of dry air affecting TD#9 is pretty significant, which will likely keep it weak for another day or so, but it still may get to Tropical Storm status today. The latest Euro takes it into the Gulf, it is still a relatively large area out for the future of TD#9, and it may fall apart if impacted by the islands too much.

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WeatherNut
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Re: Invest 94L Forecast Lounge [Re: LoisCane]
      #93283 - Tue Aug 21 2012 03:43 PM

As my tag implies...I have a better than normal understanding of Cleo...one should also remember Cleo tangled with Hispaniola and Cuba yet managed to hit S FL as a strong Cat 2 with 100mph winds in MIA. Dont forget these storms can reintensify very quickly even after all that

--------------------
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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93288 - Tue Aug 21 2012 06:59 PM


The latest GFS run (18z - link)takes it over the keys late Monday, over southwestern Florida and out into the Gulf near Tampa Bay Tuesday night, and landfall in the big Bend near Apalachee Bay on Wednesday night (same area where the worst flooding from Debby occurred)

A reminder this will probably change over time, but the trends are important to note, GFS and Euro models have historically been the better performing ones over the last few years.

Along with the above the 18Z NOGAPS (which has done horrible the last few years), is keeping it east of Florida.

Starting with the next model run (0z) some recon data will start to be inputted.


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Joeyfl
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93289 - Tue Aug 21 2012 07:15 PM

You have to give some serious respect to those models (GFS/Euro) and while we are still about 5-6 days out from possible U.S landfall like Mike said you have to keep a eye on trends and GFS has not changed much. While we had over 9+ inches from Debby and as I write this we have just got 4.33 inches in past 1.5 hrs here in St.Pete the flooding threat if this were to follow GFS would be tremendous.

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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: Joeyfl]
      #93290 - Tue Aug 21 2012 07:59 PM

Another interesting bit is how similar the discussion with Isaac may be to what Irene (another I storm) last year was.

Last year's Irene forecast lounge. This initially looked as if Florida was in the cross hairs, but eventually wound up in North Carolina and flooding in the northeast..

The biggest change was that it moved northwest over Puerto Rico early, even though initial forecasts took it over Eastern Cuba, and is very similar to what we have now with Isaac's forecast. (See Forecast History for Irene (20122) and model plots for Irene (2011)). Actually none of the models projected it going over Puerto Rico.

In short it's a bit too early to speculate while the system is when it isn't even in the Caribbean yet, I don't expect a repeat of Irene since the ridge is a bit stronger this go around, but I think it's a good framing for countering the hype that may occur.

Irene from last year (around the same Position as Isaac)


Isaac now:




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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93292 - Tue Aug 21 2012 08:36 PM

18Z Model Isaac Roundup:
GFDL: takes Isaac into south Florida. Dade or Broward County Sunday night after moving through Hispaniola, and north of Cuba. Days.Link
HWRF:Over Hispaniola and rides the north coast of Cuba, never making much further by Monday link
CMC:Over Hispaniola and stays east of Florida by Monday
GFS: takes it over the keys late Monday, over southwestern Florida and out into the Gulf near Tampa Bay Tuesday night, and landfall in the big Bend near Apalachee Bay on Wednesday night (same area where the worst flooding from Debby occurred) (18z - link)
EURO (12z): Takes it south of islands, through the Yucatan Channel into the Gulf, avoiding land the entire time. (link)

In short a lot of different possibilities at this point.


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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93294 - Tue Aug 21 2012 09:05 PM

The first round of the 0z models are out (ones from the spaghetti plots), and most are clustered around South Florida this time.

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ftlaudbob
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93295 - Tue Aug 21 2012 10:59 PM

My concern at this point is,will it slow down after Cuba and soak up all that very warm water between Cuba and South Florida.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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OrlandoDan
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Re: Invest 94L Forecast Lounge [Re: ftlaudbob]
      #93297 - Wed Aug 22 2012 06:42 AM

has not history shown a general trend to the right in the forecast track over time with these types of systems? My concerns is that if it remains rather weak will a more westerly component be present in the system and keep the track to the left?

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: OrlandoDan]
      #93298 - Wed Aug 22 2012 07:35 AM

Quote:

has not history shown a general trend to the right in the forecast track over time with these types of systems? My concerns is that if it remains rather weak will a more westerly component be present in the system and keep the track to the left?




Climatologically, yes, but not always.

The GFS model runs (6z) take it more along Cuba and then recurve it in the Gulf eventually landfalling in the Big Bend of Florida (only).next wednesday.

The CMC keeps it east of Florida

The Euro keeps it south of the Islands and enters the Gulf as a monster storm nearing Louisiana.

The trend for most everything has been slightly west this morning.

So the spread amongst some of the more reliable models is fairly large. Around the time it nears Hispaniola (Friday) is probably a good time to recheck this system.


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danielwAdministrator
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Re: Invest 94L Forecast Lounge [Re: OrlandoDan]
      #93299 - Wed Aug 22 2012 07:46 AM

You are correct. Weaker systems usually travel a bit more to the west before making a curve to the north. Somewhat akin to a tall ship with sails set low on the mast.
Stronger systems use full sails and tend to curve to the north sooner, rather than later.

Examples...
1.Storm remains weak and moves south of Cuba before turning toward the North.
2.Storm intensifies and begins to move toward the WNW or NW and crosses the Greater Antilles, which usually weaken the systems due to their topography, mountains. This weakened system has to regain it's strength and therefore moves a bit more to the west before curving North.

3.System becomes stronger, crosses the Greater Antilles early and curves northward before the Bahamas

These are just 3 of the possibilities with any system in the area of the Lower to Mid Lesser Antilles and none of these scenarios are set in stone.

See MikeC's post above for actual model forecasts.

Edited by danielw (Wed Aug 22 2012 07:49 AM)


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danielwAdministrator
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93300 - Wed Aug 22 2012 08:07 AM

I would like to add two more model forecasts to MikeC's post.

GFDL forecast just offshore of Cape Canaveral at 72 knots or 83 mph. Pressure of 974mb
Moving north up the Florida East Coast. This is at the 126 hour forecast.

HWRF forecast just offshore SE of Miami. Winds of 78.6 knots or 90 mph. Pressure of 973mb.
Movement appear to follow the forecast of the GFDL... up the Florida East Coast and just offshore. This is also at the 126 hour forecast point.

http://moe.met.fsu.edu/tcgengifs/


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MikeCAdministrator
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Re: Invest 94L Forecast Lounge [Re: danielw]
      #93302 - Wed Aug 22 2012 09:32 AM

The average of the models still puts Florida most likely, watch the model trends for west or east movements, this could come up west or east of Florida, with the middle currently being right up Florida, and the trending of the models moving slightly west.

Again, Friday should have a clearer picture. But right now the model spread is annoyingly large.




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WeatherNut
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Re: Invest 94L Forecast Lounge [Re: MikeC]
      #93310 - Wed Aug 22 2012 10:45 AM

The key here is Hispaniola. If it feels the tug north there...FL, if not enough tug...Euro solution looks credible. Looks like Isaac is in a strengthening mode right now...stronger storm better chance for a tug north. The Euro solution is a scary one...analogues for that solution are Ivan, Camille, and Katrina.
This doesn't look like an East Coast FL storm to me

--------------------
Born into Cleo (64)...been stuck on em ever since

Edited by WeatherNut (Wed Aug 22 2012 10:47 AM)


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typhoon_tip
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93311 - Wed Aug 22 2012 10:53 AM

For the general user, this may of interest - from NCEP:

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1000 AM EDT WED AUG 22 2012

VALID 12Z SUN AUG 26 2012 - 12Z WED AUG 29 2012

...HURCN ISAAC MAY IMPACT FL DURING THE D5-D7 TIME PERIOD...


THE MAJOR THREAT DURING THE MEDIUM RANGE TIME FRAME WILL BE WITH
HURCN ISAAC WHICH IS CURRENTLY CHURNING THE WATERS NEARBY THE
LESSER ANTILLES. THE LATEST NHC TRACK SUGGESTS THIS TROPICAL
SYSTEM WILL BE LOCATED JUST EAST OF CUBA BY 25/1200Z WITH A
GENERAL SHIFT TOWARD THE NORTHWEST CARRYING IT NEAR THE FL KEYS BY
27/1200Z. FCST MODELS SUGGEST A WEAKNESS IN THE MID-LEVEL RIDGE
AXIS SHOULD EVENTUALLY LIFT ISAAC TOWARD THE SERN U.S. BY MID-NEXT
WEEK. UNFORTUNATELY...THE CURRENT 06Z/00Z MODEL SUITE HAS A
VARIETY OF SOLNS PRESENTED THEREBY COMPLICATING MATTERS FOR
INTERESTED PARTIES ACRS THE SERN U.S. THE CURRENT TRACK INDICATED
BY THE NHC GENERALLY FOLLOWS THE 00Z GFS/GEFS MEAN THRU D5 WITH
HPC CONTINUING ITS GENERALLY MOTION TOWARD THE NNW INTO CNTRL GA
BY THE END OF THE PERIOD. OF COURSE...PLEASE VISIT THE LATEST
TRACK OF HURCN ISAAC ON THE NHC WEBSITE AT www.NHC.NOAA.GOV.

ACRS THE REMAINDER OF THE CONUS...THE MID/UPPER PATTERN WILL
GRADUALLY BECOME MORE HIGH AMPLITUDE IN NATURE BY EARLY NEXT WEEK.
A MEAN NEG ANOMALY SHOULD BE FEATURED JUST TO THE WEST OF BRITISH
COLUMBIA WITH THIS AXIS OF HGT FALLS GRADUALLY SPREADING SERD
TOWARD VANCOUVER ISLAND/COASTAL PAC NW BY 27/1200Z. CONSIDERING
TELECONNECTIONS UTILIZING THIS NEG ANOMALY CENTER...A BROAD AXIS
OF MID-LEVEL RIDGING IS SUGGESTED OVER THE MIDDLE OF THE CONUS
WITH A GENERAL MAX ACRS THE NRN/CNTRL PLAINS. IN THIS OMEGA BLOCK
SIGNATURE...AN ELONGATED TROF AXIS WILL BE IN PLACE ALONG THE ERN
THIRD OF THE U.S. THIS FEATURE IN PARTICULAR WILL PLAY A CRUCIAL
ROLE IN HOW MUCH LATITUDE ISAAC WILL GAIN THROUGHOUT THE MEDIUM
RANGE PERIOD.

LOOKING AT THE DETERMINISTIC/ENS GUIDANCE AS A WHOLE...THE IDEA OF
THIS HIGH-AMPLITUDE PATTERN IS CONVEYED ACRS THE BOARD.
HOWEVER...THE TIMING/STRENGTH OF THE NRN STREAM TROF MOVING THRU
THE TN/OH VALLEYS AND ERN U.S. DOES VARY WHICH HAS IMPLICATIONS OF
THE EVENTUAL PATH OF ISAAC. CURRENTLY...THE 00Z ECMWF/ECMWF ENS
MEAN MAINTAIN A STRONG ENOUGH 500-MB RIDGE TO KEEP THE SYSTEM
SOUTH OF 30N. HOWEVER...THE REMAINING GUIDANCE...ESPECIALLY THE
GFS WHICH HAS MAINTAINED ITS SOLN THE PAST 4 RUNS...INSIST ON
ISAAC BEING DRAWN NWRD. OVERALL...HPC FAVORED A SOLN COMPRISING
THE 00Z GFS/GEFS MEAN WITH SOME COMPLIMENTS FROM THE 00Z UKMET
EARLY ON GIVEN ITS FAVORABLE HANDLING OF THE NRN STREAM.


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stormtiger
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Re: Invest 94L Forecast Lounge [Re: WeatherNut]
      #93315 - Wed Aug 22 2012 11:47 AM

Dry air continues to plague Issac's development as it speeds to the West. The weaker he stays the more west it will likely go; thus taking the Eastern seabord and the Bahamas out of the picture.

This season storms have not strengthened as expected. Dry air and fast tracks west have inhibited development and most models have erred by showing the storms strengthening more than they actually did.

I think this pattern is continuing with Issac which is a large storm with larger problems in getting its act together.

I see Issac staying weak, almost missing Hispanola while turning WNW and then NW over Pilon Cuba and then Central Cuba and on towards Key West.

Accordingly the GOM from 85 longitude east should stay vigilant and the further west of the Florida peninsula the stronger it could get as it heads NNW.


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mcgowanmc
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Re: Invest 94L Forecast Lounge [Re: danielw]
      #93316 - Wed Aug 22 2012 12:17 PM

The 1935 Labor Day, 1960 Donna and 2008 Fay
are the closest analogies I can find
for a Hurricane going up the West Coast of Florida.....and that track S of PR.

Only Fay crossed Hispaniola and the narrow part of Cuba into Havana.

The 1935 Labor Day was the only one I have that literally raked the W Coast of Florida.

Donna the only Cape Verde, but like the 1935 Labor Day, going N of the Greater Antilles.

Correct me but I don't find a hurricane approximating Isaac's path.


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Ed DunhamAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93318 - Wed Aug 22 2012 01:08 PM

This is where using analogs can be deceptive, but check out Cleo in 1964. Similar early track (and time of year) but Cleo was a much stronger hurricane.

UNISYS Track of Hurricane CLEO

ED


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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: Ed Dunham]
      #93320 - Wed Aug 22 2012 02:06 PM

Current motion would lead you to believe that just maybe the ECMWF has a better handle on Issac. Today...right now, I couldn't tell you whether Florida...east side, directly over and up the peninsula or west side or up into the Gulf of Mexico. The longer Issac remains "shallow" the more west the cyclone will go...if and when Issac develops enough structurally and vertically it will then feel the tug of the upper air environment over the eastern side of the United States. There is a COL or break between the mid-continental ridge and the Bermuda ridge and a longwave trough over the NE USA extending down the Eastern US giving Issac a track to go. It is where these players will be as we go forward, how strong they will be...which ridge is stronger in however Issac is nudged one way or the other east and west. Central Georgia is in a D3 and D4 drought and could really, really use the rainfall...that said, N Florida has been drown once this year already and they don't need the extra rainfall. Ed pounded into me a bunch of years ago this 5 day rule this website has and I've adopted it over on our Facebook page this year. I realize we're all looking at Florida but I think in due time our focus will be on the Gulf Coast but that is a solid week from now...any adjustment to the left of the current track will put Issac over Cuba paralleling it over land, not taking the short route directly across from south to north; until that track is better defined Issac is not likely to be a very strong cyclone when it exits Cuba.

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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Joeyfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: berrywr]
      #93321 - Wed Aug 22 2012 02:40 PM

Isaac center has been difficult to find on satellite and radar. Isaac overall large circulation is quite sound and its inner core region has been having a hard time. Starting to lean towards Issa staying south of Hispaniola at least the inner core of the storm likely staying just south of the island however eastern Cuba still looks to take the direct hit. While this does not matter much as the storm is quite large and rainfall enhanced by the mountains in those countries will lead to mudslides and significant flooding. Beyond Cuba and I like GFS still for now with track into the FL keys and up the west coast into the Big Bend of FL. Now it Issac does not get its act together and keeps booking west it could very well make it all the way to the central Gulf but that would likely be it about as far west as the short wave trough would easily pull Issac north So I would be on guard from MS coast area east to FL and still into the south Carolia area albeit this is starting to look less likely. Time will tell. But it it does take the GFS and certainly the Euro route this could really deepen....

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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: Joeyfl]
      #93334 - Wed Aug 22 2012 08:09 PM

It seems the westerly track may be what's favored, but it may be going too far west, and I'm concerned that initialization on the models isn't that great for it. (Especially the Euro). Trends may continue west, but I think they will get overdone and eventually trend east again. In short Gulf coast through Florida and the east coast will need to watch it through the weekend.

Models may be more useful Friday, depending on how the Gultstream jet and initializations are done and if Isaac ever gets itself together, recon is still out looking for real winds, when it should be pretty easy to spot.






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MikeCAdministrator
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Re: TD#9 Forms East of the Caribbean [Re: cieldumort]
      #93335 - Wed Aug 22 2012 08:22 PM

18Z models:

GFS: Rides west coast of Florida, landfall near Big Bend
GFDL: Back East, over south and up through the middle of the Peninsula
HWRF: Rides Cuba Slowly (Run ends just northwest of Cuba with a slower storm)
EURO(12z): Gulf Storm, landfall Mississippi
CMC (12z): East of Florida, Landfall near Savannah


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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93336 - Wed Aug 22 2012 08:22 PM

I think he is slowly getting his act together,and by this time tomorrow I believe we will have Hurricane Issac.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93337 - Wed Aug 22 2012 08:31 PM

Which circulation center will win out? I think the more northerly one will in the long run, but recon reports will be interesting. I just don't see it getting its act together tonight, tomorrow perhaps.

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Mozart
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Re: TD#9 Forms East of the Caribbean [Re: MikeC]
      #93338 - Wed Aug 22 2012 08:34 PM

I can't decide between the Euro and the GFS on this one. The GFS has been good all year, but all indications I've seen is that Isaac is tracking a little south of that one, which puts the Euro into play. A few factors in play make me think the Euro has a better handle on this one, which should put the Gulf coast on alert. The NHC keeps moving the track westward and the climate conditions seem to favor keeping it down a little longer as it's not building up the strength we keep expecting it to. It's just not organizing like the other models are thinking. That being said, the key seems to be where it goes over Hispaniola. If it doesn't make the turn north, as the Euro says it won't, we could be in for a big one. SST's in the Gulf are ripe for developing a storm. Here's to hoping that nothing is right and Hispaniola and Cuba take all the bite out of this one and it lands as a minor TS that doesn't cause too much damage.

On a side note, I wouldn't mind a little rain here in the upstate of SC, but a few models make me think of TS Jerry in 1995. Flooding was intense and my brother in law received a commendation for jumping into a drainage pipe and rescuing two girls that were sucked down it. He rescued one but the other didn't make it. I don't want a repeat of that here.

--------------------
Agnes - 1972, David - 1979, Bob - 1985
Hugo - 1989
TS Jerry - 1995 (14 inches of rain in 12 hours)
Hurricane Ivan - 2004


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ralphfl
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Re: TD#9 Forms East of the Caribbean [Re: Mozart]
      #93341 - Wed Aug 22 2012 08:56 PM

Did not want to log in but had to with the other comments posted here.If you look at history from this area in the past 5 different times i can find where models have had it coming up the west coast of Florida but ending up in different far away places.

SO #1 we have history which says from here up the west coast of Florida is very low.

# 2 It was noted the Hwrf model run did not finish and this is NOT true it did finish and it is moved way west to near the euro.

What does all this mean in reality? IMO it means watch the storm and IF and When it gets its act together then we can start to think where it might go.All it is now is guessing.

I know this is the forecast lounge and people give there thoughts so my thought is anything past Friday is a pure guess that is my track

But wanted to point out the other model run did finish the HWRF and it is moved way west from its last run.

Best wishes.


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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: Ed Dunham]
      #93342 - Wed Aug 22 2012 08:58 PM

Thanx Ed.

Cleo does come close.

OF course you're correct, but again

2008 TS Fay:

http://weather.unisys.com/hurricane/atlantic/2008/FAY/track.gif

Cleo missed Hispaniola entirely and came up thru the narrow S to N
Cuba.

I can't find a Hurricane that transversed the Greater Antilles
and then made Hurricane into West Florida.

That's alot to ask.

Again. Great site. Good info.

thanx.


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93352 - Wed Aug 22 2012 11:05 PM

Center seems to be solidifying again overnight, so Isaac has a chance to get a bit more organized overnight tonight. The slight drift westward may continue tomorrow, but the ridge break may cause it to diverge a bit. Gulf coast, and Florida still need to watch it, and can't rule out the southeast entirely (although chances there are dropping).

Friday is still probably going to be best bet for seeing what the trends are.


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93359 - Thu Aug 23 2012 12:05 AM

0Z GFS run is going now, it's in the Florida straits around 93 hours away (sunday) near the Keys on Monday...

then keeps just barely offshore the west coast of Florida and starts to slow down (bad for storm surge)

Starts drifting westward away from Ft. Myers area..

Starts deepening west of Tampa (still drifting westward), then more northward (toward panhandle)

Landfall near Panama City Beach Wednesday.

Trend is a bit different from the prior run, but still has Florida (keys, west coast, and Panhandle in the target.

Still models are not to be trusted with weak systems like this, so it will likely change again.


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ralphfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93360 - Thu Aug 23 2012 12:29 AM

I agree not to be trusted when the system is weak would you be able to give a link to see the GFS earlier then i see it? cause you get it faster then i do would save me sleep thanks

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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93362 - Thu Aug 23 2012 01:11 AM

Looking at the latest WV there is no doubt he is getting much better organized.The center is more defined.This is going to be very interesting to see how it plays out.

--------------------

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Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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threwerback
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93365 - Thu Aug 23 2012 06:43 AM

Salutations from CITRUS COUNTY FLORIDA, North of Tampa about an hour in a little hamlet known as the Manatee Capital, Homosassa Springs. It appears we just might get some action from ISSAC. Should we, I'll be happy to give a amatures non scientific blow by blow. Be well and safe to those effected..
TerB

--------------------
"I would much rather be able to say I was glad I did than wished I had"
EHS

Edited by threwerback (Thu Aug 23 2012 07:03 AM)


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: threwerback]
      #93366 - Thu Aug 23 2012 07:18 AM

Models overnight and this morning have shifted slightly east.

The 6z GFS is very similar to the earlier run, but is slightly closer to the west coast of Florida, and has an interesting track back over the Atlantic from the Carolinas.

The 0Z Euro model moved eastward, and the CMC moved westward, so the alignment of the models is a bit better. It takes it over westward cuba and landfall is near Pensacola, FL. Wednesday night/Thursday.

6Z HWRF takes it in over Miami monday night, and it winds up over Tampa on Tuesday evening,

Still the initialization and structure of Isaac is poor, so changes may still occur, and adjustments both west and east will likely occur. Tomorrow hopefully should start to clear some of it up.

The large size of Isaac means it is likely to cause quite a bit of storm surge issues if it enters the Gulf and rakes along the west coast of Florida.

GFDL has landfall between somewhere Ft. Lauderdale and West Palm Beach early Monday.

See the bottom of the main page for the model links.



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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93367 - Thu Aug 23 2012 08:15 AM

The latest vortex message continues with another reformation of the center or multiple vortices; this one at 14.5N 64.2W and weakened to a tropical depression. Looking at satellite, looking at the circulation one would think it may be as farther west at 66W but I think we're looking at multiple centers once again. I'm not one to openly disagree with the NHC but I was not impressed at all with this discussion and how they determined the center fix. There is no evidence of a west-northwest and/or northwest movement as plotted on graphics. Only the ECMWF got the southwest location correct; where they got the GFS and other models being onboard, I do not know, but I continue to believe the ECMWF is the model of choice for the time being.

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Bill Berry

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doug
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93368 - Thu Aug 23 2012 08:16 AM

Old wives tale, not too scientific, but something an impressionable 9th grader took to heart in the advance of Donna in 1960 was the appearance of "mares tales" in the otherwise clear sky approaching at 40k feet from the southeast. My science teacher, a navy vet who worked in the weather service in the Philipines, called us all out to see them and then said he had seen these numerous times as cyclones approached and invariably they announced the arrival of a tropical system. He correctly predicted we would be significantly influenced by that sysstem which was still down near Puerto Rico..
This morning as I drove down at dawn from Manatee County to Lee County...there they were ...this is a large system and, although weak at the moment, will command a lot of geography. Based on this unscientific observation, I feel confident that in about 72 to 96 hours, southwest and west central Florida will experience whatever this system has to offer...we'll see,,,

--------------------
doug


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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: berrywr]
      #93369 - Thu Aug 23 2012 08:40 AM

IN 12 hours, the position has gone from
16 N to 15.4 N.

All movements to the W.

Am I missing something?

http://weather.unisys.com/ecmwf/ecmwf_500p_6d.gif

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/ecmwfloop.html

1 more shift to the West and one more shift to the East and the
EMCWF and the 'outliers' should be matching up..... :?:


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CaneTrackerInSoFl
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93370 - Thu Aug 23 2012 08:49 AM

The center is very uncertain, even now, jumping all over the place from vortice to vortice.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93371 - Thu Aug 23 2012 08:52 AM

The key here seems to be that imminent 310-315 degree 'jog'
that the NHC put in about 36 hours ago.

And then it resumes it's 280-90 degree course.

And the NHC has just shifted that jog (lasting about 6 -8 hours at current speed) with each forecast.

Take out that 'jog' and Isaac misses Hispaniola and gets close to the EMCWF.

Question: What is going to cause that jog?


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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93372 - Thu Aug 23 2012 08:54 AM


"The center is very uncertain, even now, jumping all over the place from vortice to vortice."

But doesn't that imply weakness and isn't weakness
what the CW says will move it further to the West?


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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93374 - Thu Aug 23 2012 09:25 AM

To be honest,I don't know why it is not getting stronger.There is not much dry air anymore,low shear and warm water.

http://www.ssd.noaa.gov/goes/east/watl/flash-wv.html

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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Owlguin
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93376 - Thu Aug 23 2012 10:37 AM

Dominate COC appears to be south of the NHC points. Also important to note that it has slowed down over the past several hours.

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Joeyfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: Owlguin]
      #93380 - Thu Aug 23 2012 11:32 AM

Issac s inner core continues to struggle while its overall structure is well organized. If Issac can get a defined center, i really think this storm could take off in intensification there is nothing really stopping it. I still believe this brushes by Haiti and then into Cuba before heading towards the KeyWest area Monday ish. After that I am still riding the GFS with it going up the west coast towards the big bend region. Again if this storm can get its inner core together which I believe it will soon, but I thought it would have by now, this storm could strengthern quickly before reaching Cuba followed by possibly rapid intensification in southeast Gulf.

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Lamar-Plant City
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Re: Tropical Storm Isaac Forecast Lounge [Re: Joeyfl]
      #93383 - Thu Aug 23 2012 11:55 AM

Right now, the model that seems to be handling things best out of the majors is the LBAR. It has been pretty consistent on the south edge of the cone. I am thinking that it might have the right idea. The storm stays weaker and so persists more to the west. It would then miss most of othe effects of Haiti and threaten Jamaica. Staying a bit south then allows it to strengthen more rapidly leading it to cross Cuba more sharply and heading into the Florida Straights.

--------------------
If you don't like the weather, wait 5 minutes...
2017 Season Prediction: 16/7/3


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WeatherNut
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93384 - Thu Aug 23 2012 01:20 PM

I think the next recon is going to find the center a little south of the previous fix. Its looking like the convection is finally starting to wrap around one center, although it is really hard to determine. If the center is close to where I think it is, it is well south of the NHC's forecast point.
Recon is starting to drop down from their cruising altitude so it wont be much longer before they are there

--------------------
Born into Cleo (64)...been stuck on em ever since

Edited by WeatherNut (Thu Aug 23 2012 01:23 PM)


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doug
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Re: Tropical Storm Isaac Forecast Lounge [Re: WeatherNut]
      #93392 - Thu Aug 23 2012 02:45 PM

I am amazed at the appearance of this system. If you watch the WV it seems the moisture is just evaporating especially in the vicinity where one would expect a convective core to be developing. From the visible, I would actually peg the center at 15.6 or so and not 16. This is the issue all along, the lowest point of pressure may be at 16, but the cloud presentation suggests some other point.. What shear is effecting this system? It seems some southerly shear may be part of the problem too. Still very disorganized...no evidence of consolidation or intensification.

--------------------
doug


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ralphfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93398 - Thu Aug 23 2012 03:30 PM

And i think even more of a west track will be in the 5pm update.It may not be much of a movement west but i see it going to happen this next update.

But like some have said it has to wait till we get a real center before we can say what it will do.


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Ed DunhamAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93399 - Thu Aug 23 2012 03:57 PM

Many of you have made excellent observations on the problematic center fixes over the past 24 hours. I realize that multiple vortices within a general circulation area is the prime suspect, but there seems to have been a bad-luck tendency to pinpoint the wrong one - which becomes frustrating because the real track, forecast track, and model track are seldom in sync. At 18Z I would have put the center at 14.8N - perhaps 15.2N to allow for some consistency. The18Z Advisory stated that a WNW movement had started, but I just don't see any sign of that - at least not yet. Maintaining a nebulous center around 16N will yield bad data input for the various models. Isaac remains a poorly organized system, so realize that the details of the model outputs for both track and intensity will be suspect until Isaac develops and maintains a firm center.
ED


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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: Ed Dunham]
      #93400 - Thu Aug 23 2012 04:00 PM

Earlier today, aircraft recon had a vortex message with a 14.8N; as of 23/2000Z, I have the center near 15.5N 66.5W...there is a slight donut hole there, not an eye.

--------------------
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Bill Berry

"Survived Trigonometry and Calculus I"


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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93401 - Thu Aug 23 2012 04:08 PM

Dry Saharan air is filtering into the system disrupting convective activity near the center; I had said aircraft recon posted a vortex message just before 12Z this morning at 14.8; actually it was 14.5; tops later in the morning have warmed but it was cooking pretty good at 14.5. Right now I have a center fix near 15.4N...15.5N and 66.5W and Issac is following the south side of the track envelope for the time being.

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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stormtiger
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Re: Tropical Storm Isaac Forecast Lounge [Re: berrywr]
      #93407 - Thu Aug 23 2012 05:30 PM

Issac continues to represent what the 2012 season has become, a season of storms that have not seemed to catch the genie in a bottle to become a traditional, full blown hurricane.

Dry air, East Carribean graveyard, fast motion or whatever is the main cause; it is playing havoc with the models and forecasters.

48 hours ago Issac was predicted to be at 16.6 and at 66.3 with 75 mph winds. Just 24 hours ago Issac was predicted to be at 16.7 and at 66.7 with 60 mph winds.

Right now the NHC has Issac pegged at 16.0N and at 67.1West with 40 mph winds.
And that position is sort of a compromise so they can provide a point on the map which represents a best "average" of several vortices in a larger area.

The point here is that until Issac gets better organized he could do almost anything once he organizes. Right now models are trending westward which means exactly nothing except that maybe people in Hispanola, Cuba and S Florida may let their guard down when in fact Issac could still wind up hitting Miami.

Issac is a dangerous storm. Not because of what it is, but what it could become. A weak storm, a storm not really getting its act together crossing Cuba and then suddenly intensifying in 88 degree plus GOM waters and then moving on a fast track to NO, Mobile, or Tampa before many have prepared or evacuated is a worst case scenario.

Let's hope this doesn't happen, but on a weekend people need to remain vigilant because the danger is ever present because a weak storm like Issac gaining strength rapidly in the GOM can in a sense be more dangerous than a larger storm on an obvious path.


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CoconutCandy
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Re: Tropical Storm Isaac Forecast Lounge [Re: stormtiger]
      #93408 - Thu Aug 23 2012 06:27 PM

Quote:

"... The point here is that until Issac gets better organized he could do almost anything once he organizes. *Right now models are trending westward, which means exactly nothing* ...

Issac is a dangerous storm. Not because of what it is, but what it could become. A weak storm, a storm not really getting its act together ... and then suddenly intensifying in 88 degree plus GOM waters and then moving on a fast track to NO, Mobile, or Tampa ... " - Storm Tiger



Quote:

"I realize that multiple vortices within a general circulation area is the prime suspect, but there seems to have been a bad-luck tendency to pinpoint the wrong one - which becomes frustrating because the real track, forecast track, and model track are seldom in sync. ... Isaac remains a poorly organized system, so realize that the details of the model outputs for both track and intensity will be suspect until Isaac develops and maintains a firm center." - Ed Dunham




Very nicely summed up. And I tend to agree that far too much is made of the long range model runs (3 to 5 days out) when systems are still in their formative stages, or experiencing significant deterrents of one form or another, as Isaac has now for the last few days.

Although the model runs are, of course, very interesting and useful tools, we should use heed their solutions with objectivity, even skepticism (speaking especially of the extended forecasts), until the storm is well formed, where they can initialize in a more meaningful manner and generate a more realistic prognostication.

--------------------
Prepare or Despair. Above all ...
"Don't Get Stuck on Stupid" - General Honore, following Hurricane Katrina




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doug
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Re: Tropical Storm Isaac Forecast Lounge [Re: CoconutCandy]
      #93410 - Thu Aug 23 2012 06:43 PM

Nice discussion and certainly salient points.
I am obviously not SOId on this system. I do not see any west component in the circulation envelope that is associated with a center. There are three little clusters of convection building in the 16+ 67 vicinity where NHC want to place a center, but...no w-e component there. Otherwise there is evidence of a sharp wind shift in the south but again no true west component... we will see if the convection near 16+ can maintain and take control. I find it very strange to have a "tropical storm" with this poor organization, to wit: no true circulation center.

--------------------
doug


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OrlandoDan
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93411 - Thu Aug 23 2012 06:48 PM

From Water Vapor, at 18:47 EDT, I got this baby pegged at 68W 15.5N. Anyone have a different opinion?

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

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CaneTrackerInSoFl
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Re: Tropical Storm Isaac Forecast Lounge [Re: OrlandoDan]
      #93412 - Thu Aug 23 2012 07:19 PM

Quote:

From Water Vapor, at 18:47 EDT, I got this baby pegged at 68W 15.5N. Anyone have a different opinion?




I think so too. It would be nice if this system is going to be an issue down the line, to get its act together tonight so we all can have a better idea to prepare. It looks like its giving it the old college go again this evening as the sun sets. Some very intense convection but again, lots of dry air. This is easily the oddest tropical system I can think of in a while.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



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danielwAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: OrlandoDan]
      #93415 - Thu Aug 23 2012 07:51 PM

From radar I got 68W and 15.6N... Very close, 6 miles difference.

New Advisory has Center at 16.2N/ 67.8W

Edited by danielw (Thu Aug 23 2012 08:01 PM)


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CoconutCandy
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Re: Tropical Storm Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93418 - Thu Aug 23 2012 08:02 PM

Although it's entirely conceivable (and even likely) that there remain two competing centers of circulation, my impression, based on the last few hours of the unenhanced IR animated satellite loop, is that the increasingly predominate LLCC now appears, to me, closer to 15 N, perhaps even as low as 14.8, as clearly evidenced by significant low level turning amongst strong, developing thunderstorms immediately surrounding that locus of activity.



Which bodes worse, perhaps, for a strong GOM event, due to a weaker system initialized further south of previously thought, perhaps bypassing the detrimental run up the spine of Cuba entirely, and simply crossing the narrow, relatively flat, western end of Cuba in a somewhat more perpendicular fashion (thus lessening time spent over land), ending up entering the Gulf much more intact and better able to respond quickly (aka: rapid intensification) in the very warm waters of the gulf with it's currently rather high oceanic heat content.

Also quite telling is the curvilinear 'banding' structures of moderate thunderstorms now beginning to flare up north of Hispaniola and farther NW'ward towards the Turks and Caicos and SE'ern Bahamas and also the rapidly increasing convection streaming in from Venezuela, all of which support the idea of a large circulation envelope remaining, and are perhaps the harbingers of a final 'push' to consolidate the LLCC and begin a cycle of rapid intensification.

In any event, I think we'll see significant intensification during the overnight hours tonight, perhaps dramatically so, should 'Isaac' decide to finally consolidate about one of it's myriad LLCC's.


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CaneTrackerInSoFl
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Re: Tropical Storm Isaac Forecast Lounge [Re: CoconutCandy]
      #93419 - Thu Aug 23 2012 08:08 PM

It's so difficult because I see the same center too on the unenhanced IR, but at the same time, the vortice that the NHC has pegged and the one which several of us have already stated earlier is also there. At this point, it's a battle of which center wins out.

But at least since Isaac is deciding to stick around, he looks to be finally consolidating and will give us a better idea of a forecast.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93422 - Thu Aug 23 2012 08:21 PM

Tomorrow should be the start of a clearer picture, at least I hope so, since time will run out if it stays disorganized tomorrow. Things I'm looking for overnight is how much latitude it gains (or doesn't) and if the recon finds a decent center or not.

Models have shifted west during the day, from a concentration along the west coast of Florida (except Euro) to more west of Floirda toward the western Panhandle. Euro moved more west back toward Louisiana, but the lack of a definite center really keeps me from trusting any of these. (Either west or east, which is still a possibility) The recon fix around 15.5N 67.5W is what's (Barely) dominating now it seems. Another split system tearing itself apart.

Tomorrow night it may be close enough to force watches up along the keys.


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WeatherNut
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93423 - Thu Aug 23 2012 08:33 PM

It also has been said that if the initialized center is not the dominant center...than the models aren't going to be reliable because they dont initialize properly. Also, is anyone noticing that there are vast swaths of data missing from the recon flights...its been maddening to try and follow, and its been both aircraft that sample at lower altitudes. Pressure readings are all over the place...and I still dont see any significant west wind either.

--------------------
Born into Cleo (64)...been stuck on em ever since


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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93424 - Thu Aug 23 2012 08:34 PM

As of 8pm pressure is down to 1002 and max wind is up to 45.If this trend continues overnight things maybe come clearer.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93425 - Thu Aug 23 2012 08:38 PM

The next (0z) model runs (some of the early cycles will be out soon, and late cycles starting around 11:30) have some the Gulfstream IV data in them. Special Balloon launches are starting tomorrow as well, so there will be a good deal more data points for the models and hurricane center tomorrow. The "center" mentioned above probably will change again, last night I said the northern one looked more healthy, and it wound up being the opposite.

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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: danielw]
      #93426 - Thu Aug 23 2012 09:06 PM

Land Interaction. I don't see how these models 'model' that.

And no Recorded Hurricane has traversed Hispaniola, Cuba and gone up the West side of Fl.
as a Hurricane.

The Drought. And MS has been wet. Along with Tallahassee.

Quote:

The unusual drought conditions are the result of a weather pattern known as the death ridge, said Prescott Bishop, an atmospheric science graduate student from San Antonio, Texas. “It stretches from the Rocky Mountains to the East Coast,” Bishop said. “It’s even larger than last summer’s.”

Bishop said the death ridge is a warm, high pressure weather system that has covered the Great Plains since April.
“High pressure makes the weather warmer and drier, which makes the high pressure stronger, causing even more warmth and dryness,” said Garrett Black, an atmospheric science senior from Hutchinson.

So far, no other weather pattern has broken the death ridge, which is unusual, Black said. Black did have hope that weather systems moving into the region this week could begin to curb the drought conditions.




http://kansan.com/news/2012/08/22/death-ridge-causes-drought-raises-food-prices/

So, just like Ernesto. If there's a chance of Sabine River to Morgan City,
Isaac will take it.

IF the EMCWF is correct and

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/ecmwfloop.html

Triangulates Isaac between Cuba, Jamaica and Western Haiti. the Euro will really
start looking good.

And a Cat 4 would kill the Death Ridge.

Edited by mcgowanmc (Thu Aug 23 2012 09:20 PM)


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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93427 - Thu Aug 23 2012 09:08 PM

Ships model is showing a possible RI event. 36% chance.
Prob of RI for 25 kt RI threshold= 36% is 2.8 times the sample mean(12.8%)
Prob of RI for 30 kt RI threshold= 17% is 2.0 times the sample mean( 8.4%)

I've never paid much attention to the parameter below. If those numbers are Helicity in m2/s2, that's some major spinning going on. Which is what we have been seeing on the sats.
850 MB ENV VOR 83 77 87 89 95 80 88 82 100 90 74 50 45

http://tropic.ssec.wisc.edu/real-time/wi...zoom=&time=

Edited by danielw (Thu Aug 23 2012 09:13 PM)


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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93428 - Thu Aug 23 2012 09:18 PM

Meet Hurricane Frederic 1979.
Near identical circumstances, except for Hurricane Davis being proximal to Frederic. Check the track map against what we are looking at.

http://en.wikipedia.org/wiki/Hurricane_Frederic

http://www.nhc.noaa.gov/archive/storm_wallets/atlantic/atl1979-prelim/frederic/prelim01.gif


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WeatherNut
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Re: Tropical Storm Isaac Forecast Lounge [Re: danielw]
      #93429 - Thu Aug 23 2012 09:24 PM

You know you've been looking at the SAT too long when you start to see Bozo the clown...
(a little comic relief)


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Re: Tropical Storm Isaac Forecast Lounge [Re: WeatherNut]
      #93430 - Thu Aug 23 2012 09:35 PM

Seems as though they are getting extrapolated readings under 1000 mbs now in the region of 16.6 N 68.7 W. Of course, its extrapolated but certainly the lowest that I've seen from the HDOB reports.

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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: danielw]
      #93431 - Thu Aug 23 2012 09:44 PM

Thank you, Daniel.

I knew someone would post a 'look a like'.

I was thinking of Mobile. And remembering Frederick.

But note the 'land interaction'.

Fred avoids Hispaniola coming off PR.

IT then takes the shortest path across Hispaniola
before Again taking the 'easiest' route between Haiti
and across the Southern edge of Cuba.

With the exception of the Western Tip of Cuba,
Fred never crosses land again.

Every model except EMCWF puts Isaac across the most formidable part
of Cuba with a good part of Hispaniola thrown in for good measure.

And again it moves up the very wet west side of Florida
and into the very wet Panhandle.

All my cousins, friends for the last month who went to Destin, Florabama sent back Cloudy Day pics...


I think Isaac rides along the Southern Edge of Cuba.
Like Frederick.


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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: danielw]
      #93432 - Thu Aug 23 2012 09:58 PM

If there's a center at 16.6; it's tiny; I still believe the center point of all this mess is sub 15.0N near 14.5N and 68.0W. I looked at the 24/00Z Upper Air Charts...and the mid-continental ridge strengthen ever so slightly and I see by the chart they ran a sampling mission tonight which should really help the global models tonight.

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Re: Tropical Storm Isaac Forecast Lounge [Re: danielw]
      #93433 - Thu Aug 23 2012 10:16 PM

I remember Frederick well as we had just gone through David in W Palm Beach. He meandered across Cuba and if I remember, most predictions said he wouldn't survive or do much. Then he started going north and picked up a LOT of energy across the loop current! I could see something like that happening with Isaac, but I still don't see it moving north enough to be hurt by hispanola as much as originally forecast.

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ralphfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: Lamar-Plant City]
      #93435 - Thu Aug 23 2012 10:41 PM

center at 16.0 and 67.1 hmmmm 1003 MLB not getting stronger.

(Actually the 11pm Advisory stated 1001mb.)

Edited by Ed Dunham (Thu Aug 23 2012 11:21 PM)


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berrywr
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Re: Tropical Storm Isaac Forecast Lounge [Re: ralphfl]
      #93438 - Thu Aug 23 2012 11:22 PM

I see what NHC is looking at...can't rule that location out but what concerns me is if these multiple vortices continue it sets up the possibility of that the center NHC is plotting gets obliterated by interaction with land and the area of convection to the southwest where moisture availability is much better it too could become the dominant center. There isn't a lot of activity on the north side of the system so its possible Hispanola could be spared a bit.

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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: berrywr]
      #93440 - Thu Aug 23 2012 11:32 PM

Interestingly the 0z NAM and GFS (which just initialized with some of the Gulfstream IV Recon data) are showing a pretty significant weakness in the ridge that I didn't notice before. That leads me to believe the models may shift eastward, which may be what the NHC was discussing about the short term. (longer term it may move more west)

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Lamar-Plant City
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93442 - Thu Aug 23 2012 11:44 PM

Mike....I keep hearing that stronger systems curve more and weaker systems don't. This seems to be the case as Isaac hasn't really trended NW even though the forecasts keep saying it will...but the forecasts also made it stronger. SO...if it stays south of Hispanola and Cuba and is able to strengthen more, will that cause it to curve more, shift the cone to the right later in the period, and put Florida back into play. Possible? Probable? Out of my mind?

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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93443 - Thu Aug 23 2012 11:44 PM

GFS is turning out interesting tonight, late Sunday midday it's only just made it north of Cuba, and is moving much slower. Raleighwx or instant weather maps linked on the front page is a good place to check these out if you are interested (they are still being generated)

Here comes the western jog from the NHC disccusion, Monday morning it's over the Lower/Middle Florida Keys.

Rides up west coast of Florida, just offshore of Marco island and then moves more northwesterly, dirty side of storm still fairly close to Tampa.

Landfall near Fort Walton Beach/Destin in the late afternoon, evening on Tuesday.

Track is just slightly east of earlier runs (~100 miles east at the northern gulf landfall point from the 18Z model), with a stronger storm, but slower forward motion.

.Note this model sill depends on a good initialization point, which is still somewhat suspect. So, unfortunately, expect some changes still.


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CoconutCandy
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Re: Tropical Storm Isaac Forecast Lounge [Re: berrywr]
      #93444 - Fri Aug 24 2012 12:15 AM

The story of multiple low level centers continues. There almost assuredly remains at lease a couple of low level vorticity centers embedded within the overall cloud mass, each center seemingly generating their own intermittent deep convection.

However, unlike the previous few days when deep convection came and went, the main difference tonight, now that we've entered the overnight convective maximum cycle, is the SHEER AMOUNT of deep and sustained convection of the 'bursting' variety, with very cold cloud top temps of -80 and colder, what used to be called "Hot Towers" in the old days.

Additionally, the massive thunderstorms are beginning to assume ever so telling comma shaped patterns about their respective low level centers, implying quickly training thunderstorms, very fast vertical updraft velocities, and in the process, they are imparting enormous amounts of energy via the release of stupendous amounts of latent heat of condensation and warming the middle atmosphere, feeding the warm core, lowering the central pressure and, eventually, increasing the winds and expanding the diameter of the wind field by way of an escalating, self sustaining, positive feedback mechanism.

It's Happening Right Now. This is finally(!) the night that Isaac transforms into something mightier than he's been thus far. Something the models can finally get a real handle on. Something 'more tangible' the reconnaissance missions can log into their flight recorders and make all those dropsondes more worth expending. Something to really REV UP the media engine. And, unfortunately, something to potentially inflict great discomfort and misery for hundreds of thousands still living in tents and flimsy shacks on Haiti. Something to really give the Republican Convention something to think twice about. Something that just might break Florida's unprecedented(?) string of nearly 2,500 days since it's last hurricane landfall. Now, THAT'S something to write home about !!

This scatterometer image taken just before sunset Thursday speaks volumes of what many of us have been going through, especially the superb crew at the NHC, poring over the various satellite photos exhibiting a plethora of vorticity maximums to contemplate and harangue to the Nth degree.

(Of Note here is the Total Lacking of any PURELY West Winds. Can you find any ?!? Let me know!)

It's even possible there may be some binary interaction among the centers, with the LLCC's slowly revolving about one another. But eventually they should consolidate, with only one center winning out, possibly by consuming the other.

Yes, so far 'Isaac' is a strange one for the record books. But now it's time for 'Isaac' to really show us what he is capable of.



..


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93452 - Fri Aug 24 2012 07:32 AM

Initialization, ie,center location) problems, may make the details of the models be off, but if the system stacks further south, the models will likely shift west again. Today is the big day for that, if it remains weak and disorganized it will get torn up and drift a bit west, if the stacking that appears to be happening occurs, and strengthening happens, the models may be closer to being correct (although likely to shift somewhat to the west).

The 0z euro implied a keys crossing and a western panhandle landfall, and the CMC implied a southeast florida landfall, and then another in the panhandle. GFS was keys crossing, and Destin area landfall. HWRF 6Z implies brief keys crossing and landfall in Mississippi.


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Lamar-Plant City
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93453 - Fri Aug 24 2012 07:48 AM

I think that the proof of model problems is pretty obvious in the almost straight line forecast tracks. When does a tropical system ever move in an almost straight line from southeast to northwest? I have seen them move straight WEST for quite a while, but not for 7-800 miles to the northwest very often. I think I am a bit more concerned for my area of Florida NOW than when those cones were right on us. Everyone here seems to be relaxing (MUCH less hype in the news) but when/if this gets together, that track will have to begin curving somewhere and Florida will still be in the path. Need better info soon!

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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93454 - Fri Aug 24 2012 07:52 AM

Morning All.

Could someone explain the difference
between the
OFCI
here:

http://flhurricane.com/images/2012/clark9latest.png

and the official

NHC track?

http://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_09.gif

OFCINHC official forecast (Interpolated 06 hours)

Because NHC has Gulf Shores Landfall and OFCI has Pearl River.

Thanx.

Blown Away wrote: Looks like Isaac has slowed way down? The centers are becoming stacked. Looks to me from the last pass that the FL center and the 850 center are now stacked and at about 15.4 / 70.1. That apparent NW motion in the vortex fixes will also stop. That was the FL center catching up to the SFC center. They should now start moving 285 or so. Now that they are stacked...hold on to your seatbeats. OK...going fishing.

Shurikan: In any event, the mean vector of the convective blob has been moving steadily almost due west since east of the islands; and, given Isaac's behavior so far, I'm inclined to doubt any asserted movement otherwise until I actually see the convection trend in that direction as well.


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TXEB
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93456 - Fri Aug 24 2012 08:28 AM

Quote:

Morning All.

Could someone explain the difference
between the
OFCI
here:

http://flhurricane.com/images/2012/clark9latest.png

and the official

NHC track?

http://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_09.gif

OFCINHC official forecast (Interpolated 06 hours)

Because NHC has Gulf Shores Landfall and OFCI has Pearl River.

Thanx.





I suspect the difference is a result of the times corresponding to the NHC forecast plots. The Evans OFCI plot is marked 0600 UTC, the NHC track you reference was 3 hours later at 0900 UTC or Z. The 0900 UTC plot probably reflects and update from the previous one shown in the Evans image.


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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: TXEB]
      #93458 - Fri Aug 24 2012 08:53 AM

So the Evans OFCI is an 'unofficial' NHC?

Until the NHC over rides it?

http://www.meteo.psu.edu/~gadomski/SAT_ATL/anim16ir.html

Edited by mcgowanmc (Fri Aug 24 2012 08:56 AM)


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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93459 - Fri Aug 24 2012 08:59 AM

Quote:

So the Evans OFCI is an 'unofficial' NHC?

Until the NHC over rides it?

http://www.meteo.psu.edu/~gadomski/SAT_ATL/anim16ir.html




No the Clark image has the 11PM Track. That model output map is for 6Z (2AM EDT) It's just an older official track.

You can see older official tracks here
When you look at track maps, it's vital to check the timestamp on them. Z (Zulu) time is +4 from EDT right now, so subtract 4 hours anywhere you see a Z time. Standard time is +5.

Ie, 6Z is 2AM EDT, 12Z is 8am EDT, 18Z is 2pm, 0z is 8pm. When the models refer to it, it refers to the time of initialization, not when they are available.. GFS usually shows up 3 1/2 hours after the initialization time, the euro a little later than that.

The NHC's current forecast track (including the entire cone) still seems ok, although it may drift west some today, but not much.



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doug
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93462 - Fri Aug 24 2012 09:33 AM

The system is better defined this morning than when I last looked yesterday pm and I complianed about the lack of a west wind component, and believed that the system resembled a trough rather than a closed cyclone. The center is obviously on the northern extreme of the two convective masses on the western portion of the system. As I looked this morning, the challange will be if the system will pull that mass of convection around the center, and there are some signs it may be doing that. If that process does occur, the message from NHC has been that conditions are conducive for rapid intensification...today over the next few hours we should see if this system will finally structure itself and become a more prominent feature.

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TXEB
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93465 - Fri Aug 24 2012 10:08 AM

For the next 48 hours, it looks like Isaac's major challenge will be that posed by interaction with the SW of Hispaniola and then Cuba. The NHC forecast and discussion suggests that little strengthening is expected - maybe a 10 kt boost, but mostly around 45 kts - until it emerges into the FL straights, if it lasts that long. I am not convinced that today is the critical period for Isaac. It may be more like the 48-72 hour period.

The NHC discussion at 0500 EDT indicates that Isaac is well skewed to the south with increasing altitude from the surface. This has no doubt distorted the view as seen by satellite images, which have at times given the appearance of a COC well south of the NHC reported positions. The MTCSWA , however,, shows a very well depicted cyclonic flow around the NHC's positioning. If you further look at the evolution of that analysis over the past 24 hours, it indicates clearly increasing organization at the surface level.

I suspect the big question is vertical organization over the next 48-72 hours as Isaac interacts first with Hispaniola and then Cuba. Will it pull itself into better vertical alignment, or will it remain tilted toward the south with increasing altitude?

Edited by TXEB (Fri Aug 24 2012 10:09 AM)


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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93466 - Fri Aug 24 2012 10:10 AM

Thanx Mike.

The info I was looking for.

An Ex.

An ECMWF run at 0z and 12Z
will be initiated at 8pm and 8am EDT.

So I should look for the Latest approx
3 1/2 to 4 hrs later around 4z(Midnite) and 16z(Noon EDT).

And the animated NHC tracs is exactly what I was looking for.

The latest has Isaac being 'attracted' to SW Haiti now.
With All the changes made in the last 3 days,
the only constant from the Non ECMWF models is that Isaac
seems determined to go over as much of the Greater Antilles as possible.


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doug
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Re: Tropical Storm Isaac Forecast Lounge [Re: TXEB]
      #93470 - Fri Aug 24 2012 11:02 AM

Not wishing to be argumentative, but I have correctly located the now dominant center. If Isaac can continue to to allow convection to be pulled around this center, which the last two hours or so has demonstrated is occurring...some rapid intensification i.e. approaching 70kts could occur simply because so much of this system is over the water and not being interdicted by land interaction...yet.

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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93471 - Fri Aug 24 2012 11:29 AM

As I have seen many times over the years interaction with land not only weakens a system but can also change it's direction from a forecast track.I just find it hard to believe that it will stay on the straight line over Cuba.Given how close it will be to all of South Florida where ever it comes off the north coast of Cuba and the very warm water between Cuba and S. Florida it needs to be watched VERY closely by people on both sides of S.Florida. So for me all bets are off on the track and intensity until it comes off Cuba most likely on Sunday.

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MikeCAdministrator
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93472 - Fri Aug 24 2012 11:49 AM

Won't have much time to update this afternoon, but GFS is right on 12Z, this time landfall Miami area Sunday night around 8PM. Seems a bit too far east this run?

After that it drifts westward over southwest Florida into the Gulf out around Ft. Myers Monday around 8AM. (model Run has not ended yet, so more to come)

But still worth watching to see what type of motion Isaac does today.

Will be back on much more tonight.


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Tazmanian93
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Re: Tropical Storm Isaac Forecast Lounge [Re: MikeC]
      #93473 - Fri Aug 24 2012 11:51 AM

Hasn't the GFS been fairly consistent with it's forecast track for Isaac since it's birth?

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OrlandoDan
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93474 - Fri Aug 24 2012 11:52 AM

Not positive, but looking at the WV loop as of 11:51 EDT, it looks like he is starting to wrap but losing the deep convection to the SW and S. Anyone disagree?

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Re: Tropical Storm Isaac Forecast Lounge [Re: Tazmanian93]
      #93475 - Fri Aug 24 2012 11:53 AM

Yeah. It and the Euro have been by far the most consistent when dealing with Isaac in terms of their model-to-model runs. GFS has continually floated between Miami and the Keys, so not too much difference in terms of weather.

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Re: Tropical Storm Isaac Forecast Lounge [Re: OrlandoDan]
      #93478 - Fri Aug 24 2012 11:56 AM

There is some warming but that is too be expected during the daytime. I wouldn't call it a weakening necessarily but what is more worrisome is the fact that the thunderstorms are continuing to make inroads to the northeast and north of the LLC now.

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TXEB
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Re: Tropical Storm Isaac Forecast Lounge [Re: doug]
      #93479 - Fri Aug 24 2012 11:58 AM

Isaac long floater imagery over the past 3 hours appears to be showing some evening in the convection that has been largely displaced to the SW of NHC positions over the past 24 hours. As best I can see, the apparent COC is just about on the forecast track line, but SE of where linear time interpolation of forecast points should have it. It also appears that just as convection appears to be evolving towards a more symmetrical organization, it is doing so just as the north side of Isaac begins to encounter Hispaniola's mountainous terrain.

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ralphfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93481 - Fri Aug 24 2012 12:24 PM

but that is why they have a cone and never say focus on the line right?

Edited by ralphfl (Fri Aug 24 2012 12:25 PM)


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Joeyfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: TXEB]
      #93482 - Fri Aug 24 2012 12:27 PM

Quite a shift in 12Z GFS run much further east with landfall in Miami/homestead area then out near Fort Myers area then towards the western Bigbend/central Panhandle. Most models have shifted east since late last nights run. Iam sticking with my earlier forecast with it coming in near Keywest then NNW up the west coast 40 or so miles offshore then lanfall in Big Bend near or slightly west of Cedar Key. Time will tell put its looking likely that Florida is in its sights and with it possibly getting in Gulf this could blow up stronger then Cat 1.

Edited by Joeyfl (Fri Aug 24 2012 12:34 PM)


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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: Joeyfl]
      #93483 - Fri Aug 24 2012 12:32 PM

Quote:

Quite a shift in 12Z GFS run much further west with landfall in Miami/homestead area then out near Fort Myers area then towards the western Bigbend/central Panhandle. Most models have shifted west since late last nights run. Iam sticking with my earlier forecast with it coming in near Keywest then NNW up the west coast 40 or so miles offshore then lanfall in Big Bend near or slightly west of Cedar Key. Time will tell put its looking likely that Florida is in its sights and with it possibly getting in Gulf this could blow up stronger then Cat 1.




Just so there is no confusion,The GFS has shifted east not west.

--------------------

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Joeyfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93484 - Fri Aug 24 2012 12:35 PM

Thanks Bob for that correction I edited the my post, thank you.

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OrlandoDan
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Re: Tropical Storm Isaac Forecast Lounge [Re: Joeyfl]
      #93489 - Fri Aug 24 2012 01:04 PM

Obviously and illusion (I think), but WV seems to make it look stationary with a less irregular signature, even though cloud tops have cooled a bit.

--------------------
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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: OrlandoDan]
      #93496 - Fri Aug 24 2012 01:52 PM

There is clearly a break in the ridge of high pressure in the Allantic,this is what the latest model runs including the GFS model is picking up on.This puts SE Florida back into play in a real way.
My concern,IF he slows way down or even stalls after exiting Cuba it could POSSIBLE rapidly intensity.Also people in South Florida will not have much time to prepare,also we could also be getting some affects from Issac as it comes off the coast of Cuba so driving conditions could become hazardous as early as Sunday morning.
I expect the NHC track to shift east as time goes forward.

2pm update. Pressure is down to 997 MB,no change in track YET.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


Edited by ftlaudbob (Fri Aug 24 2012 01:56 PM)


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ftlaudbob
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93497 - Fri Aug 24 2012 02:12 PM

The GFDL model latest run now has a Cat 2 Hurricane over Miami.

--------------------

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berrywr
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Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93499 - Fri Aug 24 2012 02:34 PM

Good afternoon; I'm enjoying a very much needed day off from both college and commuting and I've had a bit of time to look at the upper air charts so let's get started; last night it rained at my house and what got my attention were the movement of the cells; they were south movers. As of 24/12Z; the 500 mb upper ridge is centered over Jackson, MS, it is a 589 (decameter or 5890 meter) upper high. There are general 10 meter height falls in the entire area with height falls in advance of a 582 upper low and a progressive positive tilt shortwave trough over Eastern Nebraska, Kansas and Central Oklahoma. There is a weak 587 upper low near Houston, TX. The longwave trough that has draped the Eastern United States has moved slightly more to the east with lowest heights near Florence, SC extending through Eastern Georgia, east of Tallahassee, FL to a COL near 28N 85W in the Gulf of Mexico; heights east of the longwave trough are neutral from the previous 12 hours with the exceptions a 10 meter height fall at Jacksonville, FL and 30 meters height fall near Charleston, SC where there is a tiny cutoff low along the trough; the height fall at Charleston suggests the trough has moved a bit to the east in the past 12 hours and the mid continental ridge with two centers; one over Mississippi and the other over Northern Mexico. The Bermuda subtropical upper ridge is centered slightly west of Bermuda. A steering path for the moment boils down to whether the GFS is correct or the ECMWF with its more left track is correct. I'm aware NOAA sampled the environment around Issac for the 24/00Z model run but I see no new data on the 12Z upper charts. To date the ECMWF has performed excellent depicting where the strongest of the multiple vortices are...maybe that's pure luck; I said last night the strongest vortices are in the southwest of the broader circulation and clearly today, Issac has consolidated around that point and is much better defined today.

The $64,000 question is where Issac is going and whether Florida will be impacted. The current track suggests Issac will be over land over Cuba for a good bit of time and NHC is right; what structure will it have exiting Cuba. Issac is huge in size and Florida will be affected by both rain and possibly water pushed up ahead by moderate southerly winds on the right size of the system; I see no evidence that Issac will be a major hurricane by the time it reaches the Northern Gulf Coast. Farmers from Alabama to Central Georgia to South Carolina will welcome the rain given much is this area is in a severe to exceptional drought; particularly Central Georgia and parts of Central South Carolina; what will not welcome additional rainfall is Northern Florida and Southeastern Georgia which were impacted by Debby with an excess of two feet of rain between Tallahassee and Appalachacola (don't ask me how to spell it).

The bottom line remains how strong will the upper air players be; what upper ridge will be the strongest and which one will influence east and west the track of Issac. Clearly the general track is set with a trough between the two upper ridges.

The models have a stout 597 upper high over the Intermountain West which means blazing hot weather for them and equally stout near 594 upper ridge in the Atlantic.

I don't see this system stalling; once again it is clear what the track is; a precise point is impossible. I do have concerns about intensity but we are all going to have to wait and see what structure Issac has once in the Florida Straits; until then, it is unrealistic to predict rapid intensification or any other intensities until Issac exits Cuba.

Our thoughts and prayers go out to those in Haiti who were displaced by the earthquake who live up under tents; once the center goes by and the wet side of the storm impacts their country; like Puerto Rico today, it may be a tough weekend that lies ahead for them.

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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ralphfl
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93500 - Fri Aug 24 2012 03:15 PM


http://moe.met.fsu.edu/cgi-bin/gfdltc2.c...;hour=Animation

Edited by ralphfl (Fri Aug 24 2012 03:34 PM)


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Joeyfl
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Re: Issac & 24/12Z Upper Air Package [Re: berrywr]
      #93503 - Fri Aug 24 2012 03:20 PM

Recon just found pressure 995mb in the center just south of the south central tip of the DR. I forsee changes to the track at 5pm as NHC track lies on the western edge of the guidance envelope. I would suspect about and 30-50 mile shift right to split the extremes with Euro on far left and GFS more on the right. My thinking all along of a trip through the southern keys and up the west coast offshore with landfall in the big bend. The trough is looking as through it will be just deep enough to tug Issac more to the NNW/N after getting past the keys.

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TXEB
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Re: Issac & 24/12Z Upper Air Package [Re: Joeyfl]
      #93505 - Fri Aug 24 2012 04:07 PM

Looking at Caribbean and GOM water vapor imagery, it appears that as Isaac gets better organized, not only will it be contending with Hati and then Cuba, but also more dry air ahead. While the changes in organization and cyclonic flow over the past 8 hours have been impressive, the west side is now beginning to look a bit thin and diffuse.

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CaneTrackerInSoFl
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Re: Issac & 24/12Z Upper Air Package [Re: TXEB]
      #93506 - Fri Aug 24 2012 04:23 PM

Isaac's west is looking thin and diffuse right now, but I'm not sure if that is a function of dry air or the fact that Isaac went under a tremendous reorganization today which has cause the thunderstorms to begin wrapping around the center rather than being drained to the south and west. Can someone with more experience chime in on this?

--------------------
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dolfinatic
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Re: Issac & 24/12Z Upper Air Package [Re: CaneTrackerInSoFl]
      #93507 - Fri Aug 24 2012 04:32 PM

From vis sat it looks to me that it is just filtering the last of the dry air out of the system. If you look at haiti and DR you can see the mountains are already forcing updrafts and creating large storms. I would think as they rotate in it will fill in his western side. No expert just my observation.

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Prospero
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Re: Issac & 24/12Z Upper Air Package [Re: dolfinatic]
      #93509 - Fri Aug 24 2012 04:41 PM

I wonder, are there any seeding activities going on with this storm? The development and life of Isaac have been strange in my opinion.

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mcgowanmc
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Re: Tropical Storm Isaac Forecast Lounge [Re: ftlaudbob]
      #93510 - Fri Aug 24 2012 05:04 PM

The Closest analogy Storm I've found to
Isaac:

http://www.nhc.noaa.gov/archive/2012/graphics/al09/loop_5W.shtml

http://upload.wikimedia.org/wikipedia/co...icane_track.png

The 1915 Galveston Hurricane.


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TXEB
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Re: Tropical Storm Isaac Forecast Lounge [Re: mcgowanmc]
      #93511 - Fri Aug 24 2012 06:06 PM

Since I live about 50 miles SSW of Galveston, I feel compelled to come up with a better analog. I prefer Ernesto from 2006.

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berrywr
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Re: Issac & 24/12Z Upper Air Package [Re: Prospero]
      #93513 - Fri Aug 24 2012 06:12 PM

Dry Saharan Air Layer; what we call the SAL; it's dry between 600 millibars and 300 millibars and it is death to a tropical cyclone if caught up in it; thus far only a piece of it is entraining into the cyclone.

--------------------
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Bill Berry

"Survived Trigonometry and Calculus I"


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berrywr
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Re: Issac & 24/12Z Upper Air Package [Re: Prospero]
      #93514 - Fri Aug 24 2012 06:16 PM

One more thing...current motion is not NW; it's WNW and the center is now just south of track; I do believe it is now getting its act together; what I will be watching is how long over Cuba will it be and what it will look like upon exit; what storm was it that took up the entire Gulf of Mexico basin...Ike? It was a hurricane but it was a big, big system and the "eye" had only begun to contract before it hit Texas.

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Bill Berry

"Survived Trigonometry and Calculus I"


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MichaelA
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Re: Issac & 24/12Z Upper Air Package [Re: berrywr]
      #93515 - Fri Aug 24 2012 06:49 PM

The effects and duration of the track across Cuba will tell us what to expect from Isaac. If the track is short, then we'll be dealing with a stronger system entering the Straights of Florida. If the center lingers over Cuba, it will become more disrupted and weaker. Once we know when and where the center emerges from Cuba and over the Straights, we'll have a much better idea of what to expect in Florida/GoM. With the models trending slightly eastward again, no one should relax and discount Isaac's future as to how it will impact Florida. Isaac, by no means, is a Charley or Katrina, but being a very large system, it will impact a very large area as it moves along during the next few days. I've nearly completed my preparations, so needed or not, I'm prepared to weather a strong TS or minimal hurricane right here at my house.

--------------------
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OrlandoDan
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Re: Issac & 24/12Z Upper Air Package [Re: MichaelA]
      #93521 - Fri Aug 24 2012 07:29 PM

Finally seeing some wrap around the NW quadrant and what looks like a true COC (used IR AVN). Anyone disagree?

Edited by OrlandoDan (Fri Aug 24 2012 07:34 PM)


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MikeCAdministrator
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Re: Issac & 24/12Z Upper Air Package [Re: MichaelA]
      #93522 - Fri Aug 24 2012 07:40 PM

18Z models:

GFS: Crosses middle keys around 2PM Sunday, then clips southwest Florida, and eventually makes landfall again between Pensacola and Ft. Walton Beach around noon on Tuesday, then stalls out moving slowly over AL/MS.

EURO 12Z, Crosses Near Key West Monday around 8AM EDT, landfall near Mobile on Wednesday morning.

HWRF 18Z: ((similar to last nights 18Z, but west of earlier runs today) Clips over Key West, then moves into the Gulf straight up the Mississippi River delta into just south of New Orleans Late Tuesday night, a bad case for driving storm surge up the river, and on top of that it then stalls out over New Orleans.

GFDL 18Z ... Landfall middle Keys early Sunday afternoon. Then moves into extreme Southwest Florida, rides west coast, exits near Ft Myers, strengthens noticeably west of Tampa, but also starts to move noticeably more westerly. and landfall near Pascagoula, MS.

Recon fixes are a bit wonky still, so based on that, I think the models are very slightly too far west this time around.


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berrywr
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Re: Issac & 24/12Z Upper Air Package [Re: OrlandoDan]
      #93524 - Fri Aug 24 2012 07:53 PM

I agree; I pulled up a frame by frame IR of Issac and right at the very end there is a pronounced northward shift and it won't be long before Haiti is struck. I really want to take a look at new global models tonight and whether this shift to the east is as apparent as it was in the earlier runs; the longwave trough has shifted a bit east in the past 24 hours and I'm beginning to wonder if this puts not the West coast of FL under the gun but the East coast back in play. Issac appears to be looking better and better on satellite; curious to look at vortex data now.

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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ftlaudbob
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Re: Issac & 24/12Z Upper Air Package [Re: berrywr]
      #93525 - Fri Aug 24 2012 08:06 PM

Besides the science behind a SE FL landfall,I am getting that "gut feeling".
We will have Saturday and maybe very early Sunday to prepare,not much time.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


Edited by ftlaudbob (Fri Aug 24 2012 08:08 PM)


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Storm Cooper
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93527 - Fri Aug 24 2012 08:24 PM

This being the "lounge" I will go ahead and put this out here....this one I believe is going to bite us, and "us" meaning mutiple landfalls.

--------------------
Hurricane Season 2017 13/7/1


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ralphfl
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93529 - Fri Aug 24 2012 08:26 PM

I dunno i see the same thing i see each year and that is the center is not prefect its not round so therefore as each frame goes it gives off the look of it making a jog.If you look at 10 frames and draw a line then you have the direction it is going but 1 frame does not make a shift nor i model run *sigh* *edit* the 8pm frame i looked at from the frame before shows almost west to me*just my 2 cents*

Edited by ralphfl (Fri Aug 24 2012 08:30 PM)


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WesnWylie
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93533 - Fri Aug 24 2012 09:01 PM

Well, the models have shifted west again! The BAM models have shifted to a W FL Panhandle landfall, rather than an E FL landfall. After landfall, the BAMS & BAMM take Isaac W/NW into AR, but the BAMD continues with taking him E/NE. This makes since, though, since a stronger system is more likely to go poleward. The 00Z CMC is pretty much the same. It'll be interesting to see where this system decides to go.

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ralphfl
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Re: Issac & 24/12Z Upper Air Package [Re: WesnWylie]
      #93535 - Fri Aug 24 2012 09:22 PM

Yeah when i read i forget sometimes this is the forecast Lounge and not just hey it made a wobble 1 frame lol but yeah i see the models moving and IMO i think we will see shifts till the end.

Just remember its a cone not a line this is why Charley was supposed to hit Tampa and ended up in PC and the NHC was still right cause it was in the cone yet.

Personally i do not see them moving the cone at all this go round at all.


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TXEB
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Re: Issac & 24/12Z Upper Air Package [Re: berrywr]
      #93537 - Fri Aug 24 2012 09:32 PM

Looking at a number of sat images including Caribbean & GOM WV loops and the Isaac floater, it sure appears that he is gulping dry air on the western side. That appears to be killing convection on the far west and south sides. At the same time, it appears that convection is increasing around a much tighter and better defined core that is just past the southern tip of Hispaniola and bearing down on the south edge of Hati. With Hispaniola to the north and dry air coming in from the west, I suspect that Isaac may weaken and get shaky for the next 24 hours, but may develop a tighter and better defined core as it does so.

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Mike V
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93539 - Fri Aug 24 2012 10:12 PM

Quote:

Besides the science behind a SE FL landfall,I am getting that "gut feeling".
We will have Saturday and maybe very early Sunday to prepare,not much time.




What gives you the gut feel? Mine is I have not really seen any song birds or finches today, even when we put food out, the only regulars are ring neck doves and pigeons which never seem to leave.

I could tell you a Wilma story with a pigeon!

MikeV.


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ftlaudbob
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Re: Issac & 24/12Z Upper Air Package [Re: Mike V]
      #93540 - Fri Aug 24 2012 10:20 PM

Quote:

Quote:

Besides the science behind a SE FL landfall,I am getting that "gut feeling".
We will have Saturday and maybe very early Sunday to prepare,not much time.




What gives you the gut feel? Mine is I have not really seen any song birds or finches today, even when we put food out, the only regulars are ring neck doves and pigeons which never seem to leave.

I could tell you a Wilma story with a pigeon!

MikeV.




I almost stepped on a bird hiding on my balcony,that has never happened before.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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cosmicstorm
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93541 - Fri Aug 24 2012 10:35 PM

As for bird sighs.....they say the Ibis is the last to leave. In Green Cay wetlands this afternoon in Boynton Beach, there were still many Ibis around.

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ftlaudbob
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Re: Issac & 24/12Z Upper Air Package [Re: cosmicstorm]
      #93542 - Fri Aug 24 2012 10:39 PM

Storms that broke off from Issac have been hitting SE Fl since late afternoon.Stormy and windy night here.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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ralphfl
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93543 - Fri Aug 24 2012 10:56 PM

Track moved more east and it has slowed down some 17.7 72.5 moving NW at 13MPH

location...17.7n 72.5w
about 65 mi...100 km SSW of Port au Prince Haiti
about 245 mi...395 km se of Guantanamo Cuba
maximum sustained winds...70 mph...110 km/h
present movement...NW or 310 degrees at 14 mph...22 km/h
minimum central pressure...990 mb...29.23 inches

Read more at http://www.wunderground.com/tropical/at201209.public.html#gmzT33M7R8uifIr3.99


Edited by ralphfl (Fri Aug 24 2012 11:13 PM)


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ftlaudbob
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93544 - Fri Aug 24 2012 10:56 PM

11PM. Winds up to 70 mph,he is almost a cane.New watches and warnings.

My tropical storm watch has been upgraded to a Tropical storm warning.

Pressure down to 990 MB.

Track has been shifted a little east again.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


Edited by ftlaudbob (Fri Aug 24 2012 11:03 PM)


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CaneTrackerInSoFl
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93547 - Fri Aug 24 2012 11:12 PM

It looks like Isaac has almost ground to a halt though that could be my eyes playing tricks on me. Also appears to be wobbling almost due north during this immense slowdown? I hope Haiti comes out of this okay because there are few worse places to be than in a strengthening tropical system as it plods over you.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



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ftlaudbob
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Re: Issac & 24/12Z Upper Air Package [Re: CaneTrackerInSoFl]
      #93548 - Fri Aug 24 2012 11:18 PM

With this new track at 11pm,he will spend very little time over Cuba.That could mean a lot as far as intensification.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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Mike V
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Re: Issac & 24/12Z Upper Air Package [Re: ftlaudbob]
      #93552 - Fri Aug 24 2012 11:27 PM

Quote:



I almost stepped on a bird hiding on my balcony,that has never happened before.




Yeah, that would be unusual. Interesting with this batch of moisture that got pushed ahead of the storm. Going to be interesting navigating around here this weekend with all the flooding that will go on.

At least I hope this is not going to be another Andrew, once in a life time is enough.

MikeV


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MikeCAdministrator
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Re: Isaac Forecast Lounge [Re: cieldumort]
      #93555 - Fri Aug 24 2012 11:45 PM

0Z GFS Run (8PM initialization), started outputting at 11:30

Initialized with 1001mb (too high)

Landfall near Key Largo in the Keys, 5PM Sunday, staying in Florida bay to just offshore Marco Island (Southwest Florida)

Offshore Sarasota about 60 miles Monday morning, then moving toward 100 miles away from St. Pete.

It's moving quite a bit slower this run.

Landfall between Pensacola and Ft. Walton Beach Tuesday Night. The starts to slowly drift inland and over southern Georgia.







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Joeyfl
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93556 - Fri Aug 24 2012 11:54 PM

Issac looks like it might very well try to stair step its way through the passage between Cuba and Haiti. I see no reason right now to stray from my thinking of Keywest NNW 40 miles offshore then into big bend, time will tell.

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WeatherNut
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Re: Isaac Forecast Lounge [Re: Joeyfl]
      #93558 - Sat Aug 25 2012 12:14 AM

Looks like the ragged eye is making landfall on the Haitian Peninsula. Its also increased in forward speed. It wont spend long over land...at least the eye wont

--------------------
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OrlandoDan
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Re: Isaac Forecast Lounge [Re: WeatherNut]
      #93565 - Sat Aug 25 2012 04:54 AM

I have the eye pegged at 19.1N 73.1W. That is a bit east of the forecast track. Anyone disagree?

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

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CaneTrackerInSoFl
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93566 - Sat Aug 25 2012 05:18 AM

Right now, Isaac needs to start turning left or by the time the 8 am advisory comes out, he's not going to spend any time over Cuba, if it all.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



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OrlandoDan
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Re: Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93567 - Sat Aug 25 2012 06:31 AM

Looks like we have a low level COC at 19.6N 73.6W and a mid level at 19.1N 73.1W. Anyone disagree. The low level COC looks like it is tracking pretty close to the NHC track. Also take a look at the GFS.

--------------------
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CaneTrackerInSoFl
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93568 - Sat Aug 25 2012 06:50 AM

Doesn't look at all decoupled? I don't know what you are seeing there that would suggest that the MLC is displaced from the LLC that much, if at all right now. It looks pretty vigorous and healthy at the moment.

--------------------
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mcgowanmc
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93571 - Sat Aug 25 2012 07:48 AM

A Cape Verde crossing Martinique
Then coming up under
Hispaniola
Then taking the 'easiest' route
thru the Windward Passage
Then moving into the Atlantic
Then just offshore the length
of Cuba to the Florida Straits
Then into the GOM
Then up to Tallahassee
as a
Hurricane.

The odds are greater than putting
a CAT 4 over the Statue of Liberty.

And yet the NHC has called this from
the beginning.

Never say Never, but it'll be a while before
you see this again....

Closest analog is 1998 George and
George went over PR And the spine
of Hispaniola.

http://upload.wikimedia.org/wikipedia/co..._1998_track.png


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93573 - Sat Aug 25 2012 08:16 AM

LLC is pretty dry on the west.

--------------------
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MikeCAdministrator
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93575 - Sat Aug 25 2012 08:24 AM

Isaac's already a bit east of the 6z model runs today, and appears it won't be over Cuba for long at all, the surface trough over the keys now is keeping it sheared a bit on the west, and the mountains over Haiti are keeping it down on the right (but not tearing it up if Isaac were to go right over it)

In short it may be closer to the east side of the cone, which brings it closer toward S. Florida, albiet a bit capped in strengthening at least until it clears the islands a bit more.


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TXEB
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93583 - Sat Aug 25 2012 09:46 AM

Over the past few hours (4+) the track seems to have been more northerly (maybe 340°) than the last NHC position/direction estimates indicate.

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doug
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Re: Isaac Forecast Lounge [Re: TXEB]
      #93585 - Sat Aug 25 2012 10:03 AM

I agree with Mike's assessment and Isaac seems to be going to cut across the NE most part of the island. That means more water time as it ambles NW'd. I think the intensity forecasts will adjust, perhaps upward, once this unsettled period abates and the storm is able to perform consistently for 6-8 hours. I am not convinced it will not be able to achieve the margins of cat I-II at its peak, so a 90+ peak is possible IMO.

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doug


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: doug]
      #93590 - Sat Aug 25 2012 10:42 AM

Definitley a more northward component than predicted at the 08:00 EDT update. Be interesting how the track shifts at the 11:00 EDT update.

--------------------
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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93591 - Sat Aug 25 2012 10:50 AM

Best I can tell LLC is at 19.9N 74.3W at 10:50 EDT. Check out the RGB Floater Loop.

--------------------
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ralphfl
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Re: Isaac Forecast Lounge [Re: doug]
      #93592 - Sat Aug 25 2012 10:51 AM

the 12Z early runs are still moving it west down the road even more.Soon they will have to either adjust it or the storm start going more NW i think by tonight we should have a good idea if it is going to keep to the path or now.

I think the storm will go a little more east then is predicted at first but then i see it take the route the models show but i do think it will be stronger then what they claim it will be.i think 100mph is easy


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mcgowanmc
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Re: Isaac Forecast Lounge [Re: TXEB]
      #93593 - Sat Aug 25 2012 10:52 AM

Isaac just rolled around the 'cape' of Cuba.

Just Fing amazing.

http://www.ssd.noaa.gov/PS/TROP/floaters/09L/flash-rgb-long.html

To recap.

Isaac has crossed Martinique and the 'arm' of Haiti.

Then the Keys.

Then nothing but GOM til the Mainland.

The track the 'Ensemble' put together last Wednesday,
you'd have to say that's the Minimum amount of land crossing
possible.


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: mcgowanmc]
      #93594 - Sat Aug 25 2012 10:57 AM

I don't think it rolled around the NE corner of Cuba. I have it pegged at 19.9N 74.3W at 10:50 EDT.

--------------------
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doug
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93595 - Sat Aug 25 2012 10:57 AM

While the effect of the trough to the NW on the system has been taken into account somewhat, I also see signs that a mid-upper level vortex at the southern base of this trough (south of Cuba) is beginning to register a signature on the WV. I have thought all morning that the trough had a cyclonic spin independent of the circulation of Isaac to explain it. If there is a developing upper level cyclonic feature, that will possibly affect the direction and the development of Isaac. There is certainly a sheared western segment with Isaac and maybe this is why?

--------------------
doug


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: doug]
      #93596 - Sat Aug 25 2012 11:13 AM

Wow. Incredible dry the LLC just became on the WV Loop as of 11:13 EDT.

--------------------
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WesnWylie
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Re: Isaac Forecast Lounge [Re: doug]
      #93598 - Sat Aug 25 2012 11:16 AM Attachment (508 downloads)

I see what you're saying, Doug. I think the 500-850 mb steering layer graphic from the CIMSS site shows what you're talking about (see attached graphic).

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OrlandoDan
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Re: Isaac Forecast Lounge [Re: WesnWylie]
      #93599 - Sat Aug 25 2012 11:53 AM

The trough to the NW has a nice outflow itself right now.

--------------------
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berrywr
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Re: Isaac Forecast Lounge [Re: mcgowanmc]
      #93600 - Sat Aug 25 2012 12:19 PM

I'm looking at the upper air charts and will comment shortly...looking at visible satellite; Issac is moving towards the NNW at present and will move back over open water very, very soon. The mass of convection and rain closer to FL and moving west is not indicative of a separate tropical system; the winds aloft are hostile..30 to 40 knots in response to a deep longwave trough that while is lifting out is quite pronounced above 500 millibars shows up quite well on water vapor imagery with very dry air to the overall circulation's NW.

--------------------
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berrywr
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Issac - 25/12Z Upper Air Analysis [Re: berrywr]
      #93602 - Sat Aug 25 2012 12:49 PM

Good afternoon...We're going to begin with current satellite trends. Tropical Storm Issac as of 25/1600Z is moving NNW and is right along the extreme eastern tip of Cuba and about to exit back into open water. On water vapor imagery a good bit of the circulation surrounding the center remains somewhat dry. The big area of convection that is over FL and the surrounding waters is part of the broader circulation of Issac but winds aloft are in excess of 40 knots and are in response to a COL that is between both upper ridges, the long wave trough to the north and the inverted trough associated with Issac to the south; however, winds above 500 millibars are quite strong from the S and SW in response a full latitude longwave trough along the Eastern United States that extends well into the Gulf of Mexico. There is a 200/300 millibar upper high directly over Issac with excellent outflow. The remnants of Joyce are caught up in the Central Atlantic TUTT that extends along and near 52W longtitude to the equator. At 500 millibars there are 588 dm upper highs centered over the central coast of LA with a very narrow ridge axis extending ESE to a 588 upper high over central FL and extending ENE to the Bermuda upper ridge in the AO. The full latitude longwave trough is positive tilted to Jacksonville, FL with a very small upper low which was over SC two days ago, NC yesterday is now centered over VA. The trough inverts from Jacksonville southward to Issac. It should be noted the area that is inverted is elongated from NW to SE which is contributing to convection ongoing near FL at this time. Height falls remain generally neutral but there are slight rises along the Eastern United States east of the trough which are indicative of the trough lifting out and the Bermuda ridge slowly strengthening over the area; it is this that forecasters expect Issac to nudge itself slowly left of current track along with the narrow ridge that is in place west to east across the region N of Issac's track. We think of COLs as an area of weak steering currents but they too are simply like an intersection where multiple players meet as is the case here...Though the track cannot be precise it is clear what it is and where it will go in the broader sense; it becomes a question of what upper ridge at any given time will be the strongest. Another player in this is the shortwave in the middle of the US that is progressing east and will be what turns Issac north in a few days. This system will be welcomed in a good chunk of the country that is in need of making up rainfall deficits; others like N FL and SE GA won't welcome it. I cannot predict whether Issac is to become a major hurricane; there is no evidence to suggest today it will be but the water is hot and the upper air appears favorable for strengthening assuming the trough over the GOM in the upper levels gets out of the way.

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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danielwAdministrator
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Re: Issac - 25/12Z Upper Air Analysis [Re: berrywr]
      #93604 - Sat Aug 25 2012 01:33 PM

Excellent discussion. Saves me from having to look at the charts.

Now if we/ they can only figure out where Issac will landfall and what Category he might be. But that's down the road.


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ralphfl
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Re: Issac - 25/12Z Upper Air Analysis [Re: danielw]
      #93606 - Sat Aug 25 2012 01:56 PM

12z GFS has moved more west again i just do not see what the models see but time will tell but it has moved more west

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marydietch
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Re: Issac - 25/12Z Upper Air Analysis [Re: danielw]
      #93608 - Sat Aug 25 2012 02:33 PM

I have never posted here before but I read your discussions often. I do not know a lot about meteorology to feel confident to make my own predictions for Issac, however I do have a question. I remember as a kid going through tropical storm Marco (I am in the bradenton/sarasota area). Is it possible with the current high pressure systems and everything else going on out there that Issac may make a similar track as Marco? The current track it's on, hugging the northern coast of Cuba reminds me of Marco. Marco made more of a west movement over Cuba at first where Issac is moving more NW if not NNW (at least to me). Just my thoughts..
http://en.wikipedia.org/wiki/File:Marco_1990_track.png


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danielwAdministrator
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Re: Issac - 25/12Z Upper Air Analysis [Re: marydietch]
      #93610 - Sat Aug 25 2012 02:51 PM

The Marco track is certainly possible.
Anything from a Georges 1998 track back east ward to the Marco track is the area that the models are basically in right now.
Update: New Early BAM suite is suggesting an 89.6W Katrina type track. So anyone in SE Louisiana eastward to the Atlantic Ocean is fair game

If you are in a Watch/ Warning area, and it now appears that Issac may become a Category 2 Hurricane in the Gulf of Mexico or GOM.
Please make sure that you have the necessary items to go thru at least 72 hours without power and or water.

Edited by danielw (Sat Aug 25 2012 03:38 PM)


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Brittany
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Re: Isaac Forecast Lounge [Re: ralphfl]
      #93612 - Sat Aug 25 2012 03:36 PM

Quote:

the 12Z early runs are still moving it west down the road even more.Soon they will have to either adjust it or the storm start going more NW i think by tonight we should have a good idea if it is going to keep to the path or now.

I think the storm will go a little more east then is predicted at first but then i see it take the route the models show but i do think it will be stronger then what they claim it will be.i think 100mph is easy





would someone please explain what has happened with the GFS and the EURO switching. one going more east while the GFS going further west. I live here in Louisiana and out local meteorologists have not said much about a possible landfall in La. I would also like for someone to explain to me why the GFS is trending westward. I think it has something to do w/ a ridge, but I do not urnderstand. Wouldn't TS Isaac get stronger if the trend starts moving westward which would allow more travel time over the GOM. Thanks in advance for any input.


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ralphfl
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Re: Isaac Forecast Lounge [Re: Brittany]
      #93613 - Sat Aug 25 2012 03:46 PM

the early 18Z runs are coming in and the track is now even more west not sure if i buy it but the trend in model runs again is more west with the focal point now average in Alabama only 1 of the many early models has Florida in the track and that is clip 5 all the other early cycle runs have trended another 50-100 miles west

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danielwAdministrator
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Re: Isaac Forecast Lounge [Re: Brittany]
      #93614 - Sat Aug 25 2012 03:48 PM

You have the right idea. IF Issac does stay over the Gulf longer he Could get stronger.
But that's not written in stone. The Gulf of Mexico temperatures are more than warm enough to help strengthen Issac. But the upper air currents are playing havoc with Issac and it's almost down to a flip of a Quarter dollar to see where Issac is going.

If you can watch the Weather Channel they are right at 24/ 7 on Issac coverage.
On the old AM radio WWL-AM 870 on the dial
http://www.wwltv.com/


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: danielw]
      #93615 - Sat Aug 25 2012 04:04 PM

Is Isaac now an open wave? Let's not kid ourselves. It may be. However, intensification is certainly a very good possibility. Just wondering for those of you viewing satellite imagery, is this now an open wave?

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CaneTrackerInSoFl
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93616 - Sat Aug 25 2012 04:07 PM

I see no indication of it being an open wave. I do see the northern vorticity heading sharply NNW at the moment, however.

EDIT: It was a wobble to the NNW. Continuing to head between WNW and NW not too far from the coast. Does appear to finally be generating some convection near the northern center again, though.

--------------------
Andrew 1992, Irene 1999, Katrina 2005, Wilma 2005



Edited by CaneTrackerInSoFl (Sat Aug 25 2012 04:09 PM)


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93618 - Sat Aug 25 2012 04:13 PM

Yes. I see that now. Not an open wave. Visible satellite indicates a closed LLC.

--------------------
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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93619 - Sat Aug 25 2012 04:24 PM

Visible indicates increased convection around the LLC. Isaac may hug the coast for a while and be stronger or weaker depending on if the LLC is or is not over water or land.

--------------------
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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93620 - Sat Aug 25 2012 04:39 PM

As a follow up to Typhoon_tip's post in the main forum: Isaac is so not concentrated. How big of a threat are the spin ups in east central Florida as we move through the period. IMHO, the less concentrated the core becomes, the more the east cot of FL should be diligent. Just a question.

--------------------
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dolfinatic
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93621 - Sat Aug 25 2012 04:47 PM

Almost looks like the trough to the north is pushing the dry air out of the way and moistening the air in front of Isaac. Also appears the center is begining to emerge off the coast of Cuba. Crunch time coming soon.

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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93622 - Sat Aug 25 2012 04:49 PM

Convection increasing just to the NE of the LLC.

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ralphfl
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Re: Isaac Forecast Lounge [Re: dolfinatic]
      #93623 - Sat Aug 25 2012 04:53 PM

Maybe i am wrong but the 18Z model runs have came out ALL to the west way more yet the NHC has it at 998 MLB 60mph and the same exact track no shift at all in the track.

5PM EVERY MODEL run i have seen at 18Z is west of the current NHC track i hope they give reason in there disc cause i thought for sure they would move it more west but 998 MLB and 60mph winds moving NW AT 20

Now weather underground has the track shifted with the Florida west coast on the edge of the cone

at least in there discussion they made this clear...

Based on this expectation...
the forecast track shows Isaac moving northwestward for 12 hr or
so...followed by a turn toward the west-northwest. It is possible
the storm could make a sharper turn than forecast...as the UKMET is
showing an almost due west motion between the Florida Keys and Cuba
near the 36 hr point. The early part of the forecast track is
shifted a little to the left of the previous forecast...but still
lies to the right of the consensus models and the bulk of the
dynamical models.

So they are saying they are to the right of all the models which is good cause it keeps them in the clear if it nudges right along the west coast.


Edited by ralphfl (Sat Aug 25 2012 05:18 PM)


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Joeyfl
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93626 - Sat Aug 25 2012 06:01 PM

18z GFS is in and it is basically the same as 12Z with it moving WNW/NW towards mouth of the Mississippi River area. It interesting to note that GFS looks to be starting off a bit to far inland on its start up with actual center offshore? Overall I think it is slowly getting reorganized with GFS now on far left of guidance and 12Z Euro more east, complete flip flop.

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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93627 - Sat Aug 25 2012 06:02 PM

AVN Loop shows a good picture of where the LLC is at. As of 18:02 EDT

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MikeCAdministrator
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Re: Issac - 25/12Z Upper Air Analysis [Re: danielw]
      #93628 - Sat Aug 25 2012 06:02 PM

18Z Late cycles:

GFS, over Key West tomorrow Afternoon, then landfall New Orleans Wednesday afternoon (the west shift)

18Z GFDL, Middle keys tomorrow afternoon/evening. Wednesday morning, Bay St. Louis, MS.

.Other models will come out later, but the trend this afternoon has been to the west.





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TheOtherRick
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An Amateur Observation [Re: MikeC]
      #93636 - Sat Aug 25 2012 07:34 PM

Disclaimer: I have no clue, other than being run over by about a half dozen of these things and a few years of watching those WV loops and listening to you guys,...

...But I'd bet the ranch they are underestimating the intensity. Last couple frames of the WV sure look more impressive to me, tightening up, and pick a spot and it gets more intense.

A hech of a lot of kinetic energy and angular momemtum if the skater can bring his arms in.


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Lamar-Plant City
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Re: Issac - 25/12Z Upper Air Analysis [Re: MikeC]
      #93639 - Sat Aug 25 2012 08:20 PM

Looks to me that the models are trending west as the storm weakens (again). Doesn't that mean that if the storm strengthens, the models will trend back east? Seems to be the pattern with this storm. I am NOT letting my guard down with this storm!

--------------------
If you don't like the weather, wait 5 minutes...
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mcgowanmc
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Re: Issac - 25/12Z Upper Air Analysis [Re: MikeC]
      #93640 - Sat Aug 25 2012 08:21 PM

Isaac will be retired if it gets anywhere near Deepwater Horizon.
Isaac looks like it stretches from:

Isla de la Juventud to Key Largo to San Juan.

Edited by mcgowanmc (Sat Aug 25 2012 08:26 PM)


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cjzydeco
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Stall over SE Louisiana? [Re: TheOtherRick]
      #93642 - Sat Aug 25 2012 08:37 PM

I noticed both the 12Z and 18Z GFS have Isaac slowing and practically stalling out for something like 30+ hours as he makes landfall near the LA-MS border.

I understand the significant limitations of forecast models 72 hours out in terms of both track and intensity, but I was just wondering what those of you with more expertise thought about this motion (or lack thereof) towards the end of the run?

--------------------
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mcgowanmc
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Re: Issac - 25/12Z Upper Air Analysis [Re: danielw]
      #93643 - Sat Aug 25 2012 08:44 PM

[quote="DanielW"]Excellent discussion. Saves me from having to look at the charts.

Now if we/ they can only figure out where Issac will landfall and what Category he might be. But that's down the road.




Re BerryWR Discussion, I second that.

As to unwanted rain, at least the Georgia/N FL Drought is
over.


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Joeyfl
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Re: Issac - 25/12Z Upper Air Analysis [Re: Lamar-Plant City]
      #93644 - Sat Aug 25 2012 08:53 PM

Well there is quite a shift west in some of the 0z guidance coming in with clustering in the LA to AL areas. Will see if 0z globals are holding true to this later as they will have new upper air data put into them from the high altitude mission being conducted as we speak. Do not let your guard down in FL from Panhandle to south FL.

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mcgowanmc
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Re: Isaac Forecast Lounge [Re: Brittany]
      #93645 - Sat Aug 25 2012 08:54 PM

Quote:



Brittany:

would someone please explain what has happened with the GFS and the EURO switching. one going more east while the GFS going further west. I live here in Louisiana and out local meteorologists have not said much about a possible landfall in La. I would also like for someone to explain to me why the GFS is trending westward. I think it has something to do w/ a ridge, but I do not urnderstand. Wouldn't TS Isaac get stronger if the trend starts moving westward which would allow more travel time over the GOM. Thanks in advance for any input.




SWAG:

EURO has had Isaac missing most of Cuba to the South.
And crossing it's 'narrows' when it did.

The GFS was riding Cuba's spine.

The EURO hasn't figured Isaac to have missed Cuba to the N.

The GFS has.


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CaneTrackerInSoFl
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Re: Isaac Forecast Lounge [Re: mcgowanmc]
      #93646 - Sat Aug 25 2012 09:03 PM

Looks like Isaac is attempting to take advantage of the the diurnal max right now. Impressive flare up of thunderstorms beginning to wrap around the core of Isaac as it heads slightly more northerly. Still wouldn't be shocked if it crossed the middle keys and ended up near Florida Bay before getting out to the Gulf.

--------------------
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Trekman
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Re: Isaac Forecast Lounge [Re: CaneTrackerInSoFl]
      #93657 - Sat Aug 25 2012 10:57 PM

With the latest advisory, I am once again in the landfall area. Been awhile since we had a storm of anywhere near hurricane intensity. Biggest difference for me, is last time (Dennis), I was on Active Duty in the Florida Air National Guard. This time, I am Retired Military. Some gas stations in the area are already running low on the lower grades of gas and some have only high test.

--------------------
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MikeCAdministrator
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Re: Isaac Forecast Lounge [Re: Trekman]
      #93658 - Sat Aug 25 2012 11:04 PM

There's still a lot of uncertainty with the future track of Isaac once it's forecast to get into the Gulf. The models shifted west, but based on the NHC's discussion they haven't bought into it entirely, and split the difference. Until Isaac actually enters the Gulf it'll be difficult to pinpoint where it goes and the NHC has basically stated that. They may shift the track more west, but not until the models stabilize.

Anyway I expect the models, again, to shift eastward tomorrow.

The condition of Isaac itself right now, it's looking like it's making a run for strengthening right now, but recon won't be out to verify this for a few hours.

The wave action and surge remains probably my biggest concern because of the size of the wind field in Isaac.


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ralphfl
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Re: Isaac Forecast Lounge [Re: Trekman]
      #93659 - Sat Aug 25 2012 11:05 PM

Well the NHC did say they did not move the cone more west because they did not want to make a huge shift in 1 update hope that helps and my prayers are nobody gets hit by this but it seems likely someone will.

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ralphfl
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93660 - Sat Aug 25 2012 11:08 PM

Clark they did say they did not move the cone more west due to that so if there was a shift east even in the models it would only be back in line with where the NHC is now.Right now they are on the right of the models and from what i read it was after the storm gets near landfall that they are not buying into not its trek into the gulf


notice there wording

In about 48 hours...Isaac will be nearing
the western portion of the ridge and should move in a general
northwestward heading over the eastern Gulf of Mexico...but large
differences exist between the latest ECMWF and GFS models after
that time.

AFTER the 48 hours in which it is way out in the gulf not the next 48 hours but the time after 48 hours is what they have no faith in.

Just stating fact.Here is the model run http://www.met.sjsu.edu/weather/models/ecmwf-12/ec_sfc6-ani.html and if you look at the end of the run this is what they were talking about not agreeing


Edited by ralphfl (Sat Aug 25 2012 11:39 PM)


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dolfinatic
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93661 - Sat Aug 25 2012 11:08 PM

Sat image is looking better by the hour. Upper outflow is increasingly getting better and storms firing near center. It almost looks like cnter trying to nudge under the convection to the north. It would have to take a pretty good jog west to hit the next point. Of course the new track will come out in a half hour and it will adjust to be in line with current location. I am still perplexed on how far west thw models went in one run. Bad data??? Dont know but I dont see anything out there yet that suggests a westerly track. But then again I am not the expert. And I agree Mike C I think the models will shift back. I find it hard to believe that isaac misses the trough with him intensifying right now.

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ralphfl
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Re: Isaac Forecast Lounge [Re: dolfinatic]
      #93662 - Sat Aug 25 2012 11:12 PM

ummm 1 run? its been like a full days run not 1 run its been the 00 last night the 06 today the 12Z the 18Z and now the 00 z so way far from 1 run.

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MikeCAdministrator
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Re: Isaac Forecast Lounge [Re: cieldumort]
      #93663 - Sat Aug 25 2012 11:35 PM

0Z GFS starts out a bit too far south (over Cuba), but not enough to make too much difference I think.

It crosses the Lower/Middle Keys around 8PM Sunday, then moves west northwest into the Gulf, (doesn't really get too close to Southwest Florida)

The wind field remains huge to the northeast though, so quite a bit of Florida will get nasty/rain winds and the Tropical Storm Warnings seem legit because of that.

Gets fairly strong in the Gulf, heads northwest towards Louisiana.... Landfall there late Tuesday evening. Then rides west along the coast of Louisiana.

Two GFS runs west, if the Euro follows odds are the official track moves west at 5AM.


...


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ralphfl
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93664 - Sat Aug 25 2012 11:43 PM

I can see a TS warning easy for the whole west coast of Florida with squalls the whole day Monday BTW schools have already been called off on Monday in Manatee County.

I think the west coast will see ala TS marco type stuff it all depends on if you are near the feeder bands are not.

Best wishes to everyone and keep a eye on it


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ralphfl
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93665 - Sat Aug 25 2012 11:46 PM

Schools are closed Monday here in Manatee county already and i look for TS warnings in the next full update for the upper west coast of Florida.

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LoisCane
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93666 - Sun Aug 26 2012 12:42 AM

This is my major concern. It is not an organized Cat 1 or 2 storm. The bad weather is in several areas far from the center that is being tracked. The storm could go through the keys and S Florida will be on the "dirty side' and see huge amounts of erratic rainfall, high winds and flooding and they have been lulled into security thinking it's tracking far to the West. There are memories of storms ... HURRICANES that did that and we in miami got very little. This is a different set up... and it is still "coming together" and when it is in the middle of the Straits we will see what happened...by then Miami and other areas far away might already have had severe weather.

Storms like this are harder to predict in ways than neat, compact, small Cat 2s

--------------------
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ftlaudbob
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Re: Isaac Forecast Lounge [Re: LoisCane]
      #93667 - Sun Aug 26 2012 01:02 AM

Quote:

This is my major concern. It is not an organized Cat 1 or 2 storm. The bad weather is in several areas far from the center that is being tracked. The storm could go through the keys and S Florida will be on the "dirty side' and see huge amounts of erratic rainfall, high winds and flooding and they have been lulled into security thinking it's tracking far to the West. There are memories of storms ... HURRICANES that did that and we in miami got very little. This is a different set up... and it is still "coming together" and when it is in the middle of the Straits we will see what happened...by then Miami and other areas far away might already have had severe weather.

Storms like this are harder to predict in ways than neat, compact, small Cat 2s




Another great post,my guard is very much up tonight.I am very surprised on how strong the winds and waves are here on the beach tonight.This has been a crazy system to say the least,and I think it may have a surprise up it's sleeve.

--------------------

Survived:
Gloria,Bob,Katrina,Wilma and a bunch of tropical storms.


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berrywr
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93669 - Sun Aug 26 2012 01:43 AM

Good evening and Good morning...I'm going to keep this brief given it's early morning at my house and the GFS and ECMWF ensembles are split this evening as many of you are well aware of. Looking at the 26/00Z upper charts it is quite evident what the GFS ensemble is looking at; the narrow ridge axis that was depicted at 25/12Z from off the coast of central LA to Orlando, FL then ENE into the AO to the Bermuda upper ridge has built and strengthened by 20 meters everywhere and the longwave trough over the east has lifted out quite nicely and everything south of Charleston is inverted now and winds are from the NE aloft at 500 millibars. I went hunting for this low/mid level low NHC mentioned in their 11 pm discussion; darn if I could find it though I did pick up a surface trough...possible positive tilt shortwave along generally a west to east then northeast then north and northwest into Issac where thunderstorms are firing. I can find no definitive data to indicate what Issac is to do once in the Gulf of Mexico nor am I going to speculate where and when. Right now, the westward shift is viable if this ridge axis and multiple upper centers remains in place; however, the model have been insistent about retrograding the upper ridge west and progressing the shortwave in the middle of the country and deepening once again the long wave trough along the eastern US and what remains is all timing as to what will be where and when and the ensembles are simply split; the irony is it is now the ECMWF and its ensemble implying recurvature and sending the cyclone into northern FL coast and the GFS advertising a date with New Orleans and the Mississippi Gulf Coast; opposite from a couple of days ago. I see no evidence on satellite imagery this evening that Issac will undergo rapid intensification soon; the southern half of the cyclone is void of convection and over land, over Cuba. The long wave trough at 200/300 millibars extends south through the peninsula of FL then exiting SW FL into the GOM...wind shear analysis continues to show 30 knots from the SW aloft over convection over FL, Florida Straits near the Keys decreasing to 10 knots to near the center of Issac; overall shear is decreasing in velocity. One note, I do not input data from previous or similar tropical storms and/or hurricanes; while there may be similarities the bottom line is the data in the here and now and the data inputted into the models and their respective ensembles is unique to that storm. Only in regards to climatology what a storm's track and strength are relevant; tropical cyclones present themselves in an incredible number of personalities, flavors, hybrids and structures just to name a few; we have much to learn as why one storm does this and another with the same "ingredients" does another. Issac thus far has been a bit like the family black sheep; different!

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: berrywr]
      #93670 - Sun Aug 26 2012 02:10 AM

After all this???????

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

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mcgowanmc
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Re: Isaac Forecast Lounge [Re: berrywr]
      #93679 - Sun Aug 26 2012 08:45 AM

Quote:

berrywr: I see no evidence on satellite imagery this evening that Issac will undergo rapid intensification soon; the southern half of the cyclone is void of convection and over land, over Cuba. The long wave trough at 200/300 millibars extends south through the peninsula of FL then exiting SW FL into the GOM...wind shear analysis continues to show 30 knots from the SW aloft over convection over FL, Florida Straits near the Keys decreasing to 10 knots to near the center of Issac; overall shear is decreasing in velocity. One note, I do not input data from previous or similar tropical storms and/or hurricanes; while there may be similarities the bottom line is the data in the here and now and the data inputted into the models and their respective ensembles is unique to that storm.




And that's why I do history. There's only so many ways to write a book
and to 'run' a hurricane.

Isaac's now in hurricane alley.

There's a reason everyone from Mikanopy to Spanish galleons to CentCom
have picked Tampa Bay as HQ....

Isaac now follows the Classic Retired Analogs:

It tracked nearly due westward, eventually becoming clearly identifiable on satellite imagery on August 9. By that time, the thunderstorm activity concentrated into a circular area of convection. The next day, it moved through the Lesser Antilles, although there was no evidence of a closed circulation. On August 13, the wave passed near or over the southern coast of Jamaica as its convection spread northeastward through the Bahamas. Subsequently it began a slower motion to the northwest. On August 14, the Hurricane Hunters flew to investigate for a closed circulation near the Bahamas as well as near the Cayman Islands.[2] The crew observed a developing center in the western Caribbean, and winds quickly reached tropical storm status. It is estimated Tropical Storm Camille developed late on August 14 with winds of 60 mph (95 km/h), about 50 miles (80 km) west-northwest of Grand Cayman.[2][3]


Initially, Hurricane Camille was forecast to turn northeastward toward the Florida panhandle. Instead, it continued northwestward and rapidly intensified. Its eye contracted to a diameter of less than 8 miles (13 km), and strong rainbands developed around the entire hurricane. Due to the small eye, Hurricane Hunters at first had difficulties in obtaining the strength; however a flight late on August 16 recorded a very low pressure of 908 hectopascals (26.8 inHg), with winds estimated at 150 mph (240 km/h).[2] At the time, it was not expected to intensify further.[3]


Wiki


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mcgowanmc
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Re: Isaac Forecast Lounge [Re: mcgowanmc]
      #93680 - Sun Aug 26 2012 08:57 AM

Camille went right over my school.

The Brother said the anemometer blew off at 210.

Katrina put 20+ ft all the way to the CSX tracks.

CSX wanted to then build 10 miles inland.
Above I 10.

Someone nixed that idea.

The school was rebuilt to withstand a Katrina.
It and the church across the street, pews stacked on the alter
was all I could recognize.

The new US 90 bridge should hold.

Don't know how they reworked the CSX bridge crossing Bay St Louis.

A stalled Isaac in the MS/Pearl River Estuary, you might as well
build a levee from River Ridge to Claiborne to I 10 to the Jackson Barracks
at the industrial Canal.

Give every (school, city, county) bus driver in NO a bus and tell 'em to fill 'er up
and get N of the Lake.

A stalled CAT 3 in the MS River Estuary, they'll either have to blow the
S Levees and lose the MS
or
save the MS and lose NO.


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ralphfl
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93682 - Sun Aug 26 2012 09:48 AM

did any models shift back east so far today? was checking i see more west then yesterday


Prediction Miami area will see small squalls less then afternoon TS type since it seems now to be headed farther and father west.

I see the West coast of Florida with small squalls from Tampa south to around Sarasota and then some maybe larger squalls with TS winds.

All in all East coast FL nothing

West coast some small squalls

SW coast Florida some squalls

Now time to worry for those who will be in its path...

Edited by ralphfl (Sun Aug 26 2012 10:22 AM)


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Ed DunhamAdministrator
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Admin Note [Re: mcgowanmc]
      #93685 - Sun Aug 26 2012 10:38 AM

Just a request to stay on topic - and a reminder that we do have a Hurricane History Forum.
Thanks,
ED


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: Ed Dunham]
      #93686 - Sun Aug 26 2012 10:52 AM

Looks like Isaac is fighting off the dry air intrusion to his SW quite nicely - from WV Lop as of 10:52 EDT.

Edited by Ed Dunham (Sun Aug 26 2012 10:57 AM)


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MikeCAdministrator
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93689 - Sun Aug 26 2012 11:52 AM

12Z GFS, west even more, stalls out along the coast south of Morgan City, LA Wednesday morning. Puts New Orleans with the dirty side of the storm, and then SLOWLY moves westward in or along the coast of Louisiana.


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cjzydeco
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93692 - Sun Aug 26 2012 12:18 PM

Quote:

12Z GFS, west even more, stalls out along the coast south of Morgan City, LA Wednesday morning. Puts New Orleans with the dirty side of the storm, and then SLOWLY moves westward in or along the coast of Louisiana.





I was looking at tide tables--and someone please correct me if I'm wrong--but the timing of landfall predicted by the GFS (00z Aug 29) would coincide closely with high tide in the New Canal (6:28 PM CDT).

~danielw: I looked at the Rigolets tides for the 28th and 29th and the 00Z arrival of Issac would be just after the High Astronomical Tide. I other words the water would pile up before and after High Tide. The tide wouldn't go out it would just get higher. This is based on the Rigolets and Lakes Bourne and Ponchartrain tides. Water gets blown into these areas and can't get out. ( Well it can get out but it ain't pretty, floods New Orleans if it goes out that way)

Edited by danielw (Sun Aug 26 2012 12:34 PM)


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Hawkeyewx
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Re: Isaac Forecast Lounge [Re: MikeC]
      #93693 - Sun Aug 26 2012 12:22 PM

The latest GFS track might actually be the best case scenario. Isaac would gradually weaken as it skimmed along the Louisiana coast, with the strongest wind affecting mostly coastal swampland. Then the extreme drought-stricken middle of the country would get a hugely beneficial tropical rain.

Moderator Note: The comment that Isaac would weaken in the latest GFS track is an assumption actually not made by that model. These last few GFS runs actually look like a horrible case scenario: large, major hurricane in the north-central GOM only slowly moving west-northwestward, with very little, or no weakening to speak of. These GFS runs suggest not hours, but potentially days of unrelenting storm surge, heavy rain and hurricane-force winds on the northern gulf coast. Variations on that general theme were in the 25/18z , 26/00z, 26/06z, and 26/12z runs, with no significant weakening indicated to speak of.


Ciel

Edited by cieldumort (Sun Aug 26 2012 01:58 PM)


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: Hawkeyewx]
      #93695 - Sun Aug 26 2012 01:32 PM

Latest Key West radar (as of 13:31 EDT) shows a hint of consolidation and compression of the eye.

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

Personal Weather Station: https://www.wunderground.com/dashboard/pws/KFLLONGW67


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93696 - Sun Aug 26 2012 01:35 PM

Convestion also exploding to the south.

--------------------
Keith (1988), Charley (2004), Frances (2004) , Jeanne (2004), Fay (2008), Mathew (2016), Irma (2017), Dorian (2019)

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ralphfl
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Re: Isaac Forecast Lounge [Re: OrlandoDan]
      #93699 - Sun Aug 26 2012 02:37 PM

and also the 2pm has not bumped the winds up at all.

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berrywr
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Tropical Storm/Hurricane Issac - 26/12Z Upper Air Analysis [Re: OrlandoDan]
      #93700 - Sun Aug 26 2012 02:44 PM

I have a date cutting my yard when I'm done...my apologies for being a bit later than usual..however, it is Sunday! The models continue to be in two camps; with the ECMWF and UKMET being in the east camp and the GFS and it's kissing cousins making LA/MS having Katrina flashbacks. At 500 millibars the upper ridge axis I have talked about over the past 36 hours continues to remain in place and is building and heights have now risen to an average of 5900 meters with a 592 dm center over Southern Alabama; the axis is slightly inland and extends the entire length of the Gulf coast. The upper low over VA has cut itself off further aloft at 300/200 millibar which is evident on water vapor imagery and shear analysis reflecting about 20 to 25 knots from the SSW to NNE out ahead of Issac; it has weakened but nevertheless should inhibit rapid intensification despite ideal conditions in every other way. What the ECMWF and UKMET are picking up is what remains of an earlier in the week longwave trough which has lifted out quite nicely but what remains is this upper low and it's adjoining shortwave trough which lies just west of Charleston, SC southwestward to a position between Tallahassee and Jacksonville where there is a COL in the northeastern GOM where the upper ridge axes and shortwave trough and Issac's inverted trough meet. The other player in all of this is a shortwave trough in the middle part of the country expected to move east and deepens the longwave trough again along the eastern US. I'm still waiting for whether an upper ridge sets up shop in the Inter-Mountain West as models continue to advertise. There is a very small window of opportunity if Issac opts to make its welcome along the Alabama/Florida coast; otherwise it does appear that the narrow ridge axis along the Gulf coast will be strong enough to; one, the trough in the plains states to bypass the cyclone and two, steer the system west and then northward as the models have been advertising with this IM west upper ridge center that has yet to develop. Radar imagery out of Key West has Issac moving generally NW but there has been a bit of wobbling to the NNW. Y'all have fun!

--------------------
Sincerely,

Bill Berry

"Survived Trigonometry and Calculus I"


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kromdog
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Re: Tropical Storm/Hurricane Issac - 26/12Z Upper Air Analysis [Re: berrywr]
      #93701 - Sun Aug 26 2012 02:59 PM

2PM NOAA Discussion

THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL
MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL
RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS
A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE...
THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY
3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE
OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS
ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD
ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS
GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST.


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CoconutCandy
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Re: Isaac Forecast Lounge [Re: berrywr]
      #93703 - Sun Aug 26 2012 03:26 PM

Quote:

I can find no definitive data to indicate what Issac is to do once in the Gulf of Mexico nor am I going to speculate where and when. ... I see no evidence on satellite imagery this evening that Isaac will undergo rapid intensification soon; the southern half of the cyclone is void of convection and over land ... - by Berrywr on Saturday Night




My, what a difference a day can make with regard to ongoing storm developments !!

Tropical Storm Isaac has exhibited increasing signs of consolidation and organization today. As the day began, the issue of multiple vorticies remained in evidence, with at least 2 of them, near and over Cuba and another possibly lurking to the NE.

Additionally, and more significantly, Isaac was essentially roughly half a storm, with all it's (meager at best) deep convection and associated cloud and shower envelope largely confined to the NE SemiCircle, with it's north-westernmost extent of this "half pie" arcing back across Florida, providing intermittent bursts of frenzied winds and driving rains across the southern half of the peninsula.

But from the 5 1/2 hour time lapse visible satellite loop shown below, you can clearly see that Isaac rapidly attained a much more symmetrical appearance as the ancillary vorticies weakened and spun down over Cuba and deep, sustained convection formed near a still sloppy and rather elongated center of circulation.

Then, slowly but surely, the innermost structure began contracting down and intensifying and a steadily improving long range Doppler signature out of Key West began to confirm, finally, what has been a long time coming: A solid trend towards intensification.



In the final few frames of the satellite loop, you can certainly notice the flareup of deep convection on BOTH sides of the 'developing eyewall', which is also borne out on Doppler. The deepest convection has formed a 'partial eyewall' in Isaac's NW quad and has, within the hour, just lashed the southern Keys and Key West.

With a steadily improving and developing eyewall structure, and with the approaching overnight convective maxima cycle, I can reasonably assume that Isaac may finally attain that which has eluded him thus far: A well developed eyewall and it's attendant Hurricane status.

Here's my question: With plenty of high oceanic heat content ahead of the storm, and assuming ongoing and increasing organization, and (presumably) lessening shear in the Gulf, and a good, long track run up the gulf to the MS delta region (or points eastwards), WHAT is to prevent Isaac from rapid intensification, perhaps to Major proportions?

It's already HUGE. If it were to also attain high end Cat 2 or even Cat 3 strength, we'd have a real problem to deal with, especially N.O., should Isaac ultimately track near or over that city, considering the coincident near-full moon tidal issues with the flooding of surrounding canals, lakes, etc., as has been discussed. Your thoughts?


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upsman
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Re: Isaac Forecast Lounge [Re: CoconutCandy]
      #93708 - Sun Aug 26 2012 04:33 PM

looking at a visible satellite loop and man this thing is forming an eye wall pdq! wild how it is following almost the ssame track as Katrina too and dates close too crazy stuff. http://www.intellicast.com/Storm/Hurrica...mp;enlarge=true

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kromdog
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Re: Isaac Forecast Lounge [Re: upsman]
      #93712 - Sun Aug 26 2012 05:12 PM

5PM NOAA Discussion


ISAAC HAS MOVED A LITTLE TO THE LEFT OF PREVIOUS PROJECTIONS AND
CENTER FIXES YIELD A 6- TO 12-HOUR AVERAGED MOTION OF 295/15. THE
TRACK FORECAST CONTINUES TO BE CHALLENGING. THE DYNAMICAL MODELS
SHOW THE TROPICAL STORM/HURRICANE GRADUALLY TURNING TO THE RIGHT
AND HEADING FOR A BREAK IN THE SUBTROPICAL RIDGE. HOWEVER...THERE
ARE SUBSTANTIAL DIFFERENCES AMONG THE MOST RELIABLE MODELS AS TO
WHERE ISAAC MIGHT CROSS THE NORTHERN GULF COAST. THE U.K. MET.
OFFICE AND ECMWF MODELS ARE ABOUT 300 N MI TO THE EAST OF THE GFS
AT LANDFALL. IT SHOULD BE NOTED THAT NEARLY ALL OF THE GFS ENSMEBLE
MEMBERS ARE EAST OF THE GFS CONTROL TRACK. BECAUSE OF THE WIDE
MODEL SPREAD...THERE CONTINUES TO BE GREATER THAN USUAL TRACK
FORECAST UNCERTAINTY.

THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
FORECAST TRACK DUE TO FORECAST UNCERTAINTIES AND THE FACT THAT
SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER.


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ralphfl
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Re: Isaac Forecast Lounge [Re: upsman]
      #93713 - Sun Aug 26 2012 05:22 PM

lost more down to 55ph soo could be down to 50 and keep going west IMO

Although satellite and radar images have suggested that the tropical
cyclone was becoming a little better organized...an Air Force
hurricane hunter aircraft investigating Isaac this afternoon have
found that there has been no strengthening of the storm.
Flight-level and SFMR-observed winds support an intensity of 50 kt.
There is still a well-established upper-level outflow pattern over
the system..


Edited by ralphfl (Sun Aug 26 2012 05:24 PM)


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mcgowanmc
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Re: Isaac Forecast Lounge [Re: cjzydeco]
      #93732 - Sun Aug 26 2012 09:28 PM

Quote:

Quote:

12Z GFS, west even more, stalls out along the coast south of Morgan City, LA Wednesday morning. Puts New Orleans with the dirty side of the storm, and then SLOWLY moves westward in or along the coast of Louisiana.




The tide wouldn't go out it would just get higher. This is based on the Rigolets and Lakes Bourne and Ponchartrain tides. Water gets blown into these areas and can't get out. ( Well it can get out but it ain't pretty, floods New Orleans if it goes out that way)





http://www.youtube.com/watch?feature=player_embedded&v=LyBIiLYLBRY

NO can't win. It's a huge pile of mud on the edge of the MS Canyon.
And it's sunk 7 inches, the Gulf has risen X since Katrina.

A stalled Cat 3 20/30 miles N of Deepwater Horizon,
NO will be right back to Sep 1, 2005.

Minus Airport and Superdome for Emergency Shelter.

Edited by mcgowanmc (Sun Aug 26 2012 09:33 PM)


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TXEB
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Re: Isaac Forecast Lounge [Re: kromdog]
      #93736 - Sun Aug 26 2012 09:48 PM

Right now I just don't see much to suggest a high probability of a significant turn northward. SWAG based largely on local and past experience, and little more, but right now I would guess little turn, a close approach to the LA delta region, a jog west, with landfall late Wednesday morning around the TX/LA border - Cameron, LA to Sabine Pass - as a strong Cat 2, possibly Cat 3. Pretty close to HWRF 1800Z prediction.

Edited by TXEB (Sun Aug 26 2012 10:13 PM)


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ralphfl
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Re: Isaac Forecast Lounge [Re: TXEB]
      #93741 - Sun Aug 26 2012 10:16 PM

ive have been in the euro mode camp since the start with the wnw but each model run has went west with no backing to the east

Florida will be normal we get TS each day just a little extra wn but some much needed rain in some areas.

Here is praying it does not get stronger


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OrlandoDan
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Re: Isaac Forecast Lounge [Re: ralphfl]
      #93759 - Mon Aug 27 2012 06:16 AM

A significant portion of dry air entering from the SE. It also looks like the main area of convection really took a westerly jog in the lat few frames of the WV Loop.

--------------------
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mcgowanmc
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