MikeCAdministrator
(Admin)
Thu Jul 15 2010 07:04 PM
Watching Two Systems

6:30 PM Update 21 July 2010

There is still no low level circulation is correct, if one were to form tomorrow it would probably be right near or just south of the Caicos islands in the Caicos Bank. But the make or break will be tomorrow.

It has on more night of shear (tonight) to survive before conditions improve tomorrow. The upper level low is moving out toward the west now, away from the system.. If it makes it through relatively intact tonight then it has a real shot for development tomorrow. Track wise it's still seems south Florida/straits is the odds favorite, again deepening if it develops tomorrow or not. If it doesn't develop tomorrow, chances drop off greatly it will this side of Florida.

Thankfully, odds are that it is just a rainmaker for south Florida.



A new area (98L) Is being tracked in the Bay of Campeche, this was the wave mentioned earlier in the week in the NHC outlook that was in the West Caribbean at the time at 20.0N 92.8W, more to come on this system soon.

Another area in the far eastern Caribbean may be worth watching next week.

{{StormLinks|Invest 97|97|3|2010|1|97L|}}
{{StormLinks|Invest 98|98|4|2010|2|98L|}}
{{StormCarib}}

{{EastFloridaRadar}}


7:00 AM Update 21 July 2010
The tropical wave north of Hispaniola (97L) has diminished in activity, but overall development chances are still high for the next 48 hours, at around 60%.

The good news is that it will likely remain weaker, which means a more westerly track, at least in the short term, is more likely. The most likely scenario at the moment is rain or a moderate Tropical Storm approaching south Florida Friday or Saturday, but it could take longer if the forward motion of the system remains erratic or if the center changes. If it remains weaker for much longer, the further south it would likely stay, and may miss Florida to the south (although South Florida may still get rain out of it)



Recon is scheduled to head out there this afternoon. (Update: This was canceled) It is possible a center forms further east of where the current estimate is, which would drag the time line out longer. The forecast models that take it further west (and through the Florida straits) keep the system weak.

The system's convection will probably re-fire this afternoon and have a real shot at development Tomorrow.

It's under the influence of shear around the edges of the system, and the upper level low to the northwest of the system is keeping the wave down. In short things are trending back in the right direction for less of an impact. Those in the Bahamas, Keys, Central and South Florida should continue to monitor the system, as there is potential for things to change rapidly.



7:30 PM Update 20 July 2010

The chances for the wave to develop within 48 hours have increased to 60%, and indeed, by Thursday we could have a system. The wave is currently near 19.4N 67.4W and is moving generally west northwest around 10 mph.

Those in the Bahamas will need to watch this one closely, and those in South Florida will want to monitor this system very closely if it develops. Note if it were to develop, then tropical storm or hurricane watches/warnings would likely go up for South Florida as early as Thursday, earlier for parts of the Bahamas. Those in East Central Florida also will want to watch for any trends that may bring it further north.



If it were to make landfall in Florida, it would likely be Friday.

Some people are still having missing images on flhurricane.com, we have made another tweak to fix it, but it may take a few hours for it to show up.

7:00 AM Update 20 July 2010
Not much has changed since yesterday on the wave north of Puerto Rico.

It still remains under heavy influence from an upper level low and a lot of negative factors for development, which may not let up until Thursday. There is a 30% chance it could develop in the next 48 hours, but currently it doesn't look all that impressive. The center was actually relocated a little southeast of yesterday's position.

Track forecast is fairly similar, it's moving slowly generally westward and how far south it stays depends on the riding. Most likely it stays in South Florida/Florida Straits (or even further south) nd brings some rain to the area. However that may change, once it gets near the Bahamas we may have a better idea of the future of the system.

Currently it's bringing heavy rain to eastern Puerto Rico.



7:00 AM Update 19 July 2010
A new area in the Leeward islands and just north, is now being tracked as 97L. This system will have to be closely watched over next several days as it is likely to enter the Bahamas.

This wave currently has a 20% chance for development. In the near term, shear will likely keep this from developing, but once it gets closer to the Bahamas that begins to drop off, so there is some chance for slow development then. Those in Central and mostly South Florida will want to watch this system as it nears the Bahamas, but most likely it will not have much of an impact at all.

What this wave has going against it is the upper level environment, and that should keep it in check in the short term.



97L currently is rather disorganized, an upper level low near the system is enhancing convection right now. It may not make it until Thursday when conditions begin to improve. Estimate of location is 19.2N 65.0W

A rather strong ridge building to the north is likely to keep this system on a westward track, into the Bahamas and possibly south Florida later (or more likely the Florida Straits or south) in the period, most likely as a rain maker. It will have to be watched for development since systems can change rapidly over that area.

That said, If it were to develop, the most likely time would be around Thursday. This is when shear may abate some, and an upper high may get a foothold. Right now it's dealing with 20-30 knots of wind shear, and an upper level low to the northwest of the system. Ironically, if the upper level low moves far enough away to the west and dies out, it may wind up having a play in spinning up 97L.

This week will likely see an increase in overall activity from the last two weeks, especially the latter half of this week..

The other area in the West Caribbean isn't being tracked as an invest yet, but it may be worth watching if it gets to the Bay of Campeche intact. It also has a 20% chance for development.

One of flhurricane's image servers went down over the weekend, there will be a day or so where some of you may see blank images, but it should clear up by the end of the day as the dns changes propagate.

3:30 PM Update 16 July 2010
Although nothing appears to be developing over the weekend, there are a few areas being watched, but nothing being tracked as an "Invest area"

There is a low area over the northern Gulf of Mexico that has a small chance to develop, but is not likely. It's worth watching only for the proximity to land. The hurricane center gives this area about a 10% chance.

Another area in the Western Caribbean is approaching land and is running out of time to develop, the hurricane center gives this one about a 10% chance.

Another area, not mentioned by the hurricane center, in the Florida Straits. This upper level low south of Florida appears to have developed a weak mid to low level circulation near 23.5N 80.5W at 16/14Z. The upper low is moving west at about 6 knots and is situated just off the north coast of central Cuba. Westerly windshear at 25mph should curtail any further development for the next couple of days.

In short a few things to watch, but nothing to track.

Original Update
The generally slow pattern of mid-July continues. It will likely become more active in a few weeks, but there is not much going on right now.

There is one area in the Central Atlantic, currently not being tracked as an invest, that the national hurricane center gives a 10% chance for development. With the sal north of it, I'd give it a little less, but it is something to watch over the next few days.

Most likely nothing will come out of it.


berrywr
(Weather Analyst)
Thu Jul 15 2010 09:14 PM
Area in GOM off W FL

There is a good bit of "non-tropical" activity in the Gulf of Mexico. There continues to be a persistent long wave trough right along to just off the Eastern US which last week a large cutoff upper low was parked off the NC/SC coast. Winds aloft are somewhat light and though in the here and now this activity becoming tropical is not likely; however, if thunderstorms persists it is something that will bear watching in the days ahead.

Another area of activity is once again down near the country of Panama, however activity there is more likely in the Pacific basin.

Area of activity NHC is eyeballing will have an opportunity for development near and along its track for the next several days; however winds aloft are not favorable from the Lesser Antilles extending west-northwest through the islands to the Bahamas.


WesnWylie
(Weather Guru)
Thu Jul 15 2010 10:07 PM
Re: Area in GOM off W FL

I agree that the area in the Gulf of Mexico could be something to watch for in
the next few days. If any development were to occur, it would likely come from
the central or southern part of the trough rather than up by Florida. Another
factor that would favor in development of this trough is the fact that it would be
right on top of the Gulf Loop Current in a day or so. Still, with that being said,
the chance for development is very low right now.

Update: Well, the NHC has tagged another area of interest. This one is in the
Western Caribbean at 10%. We'll have to wait and see about this area since, as the
NHC has pointed out, any development would be slow to occur.
My only concerns are the following:
*The somewhat strong shear that it is in; however, the models show that weaken-
ing in the next few days.
* Regardless of development, it will likely have some land interaction in about three
days.


doug
(Weather Analyst)
Fri Jul 16 2010 12:34 PM
Re: Area in GOM off W FL

What is interesting about the western Carribean is that NOGAPS has been on this for several days. It does bear watching.

JoshuaK
(Weather Guru)
Fri Jul 16 2010 04:23 PM
Re: Area in GOM off W FL

Even with the northerly shear apparently affecting the ULL just SE of Miami, there appears to be a pretty solid and consitent ball of convection near what appears to be the center of circulation. I'll definitly be watching this system to see if there is a transition into a LLL as it moves into the GoM. IMO, this system bears the most watching right now in the Atlantic Basin.

WesnWylie
(Weather Guru)
Fri Jul 16 2010 06:08 PM
Trough in the Gulf of Mexico

The NHC has given the area in the Gulf of Mexico, which has been talked about for the past few
days, a 10% chance of development. The trough appears to be situated in an area of lower shear
compared to other parts of the Western Atlantic basin; however, at this time, it is still not by any
means in favorable conditions. Since the trough is very elongated right now, any development
would likely not be in the near future. The official NHC text is below.

SHOWERS AND THUNDERSTORMS OVER THE NORTHERN GULF OF MEXICO ARE
ASSOCIATED WITH A TROUGH OF LOW PRESSURE. SURFACE PRESSURES ARE
NOT FALLING SIGNIFICANTLY...AND DEVELOPMENT...IF ANY...WILL BE SLOW
TO OCCUR AS THE SYSTEM MOVES SLOWLY WESTWARD OR WEST-NORTHWESTWARD
OVER THE NEXT COUPLE OF DAYS.

As far as the upper-level low near South Florida goes, the shear appears to be taking its toll on it.

Update: The NWS Office in Lake Charles, Louisiana mentions the trough in the gulf.

AS WE HAVE SEEN WITH PAST WAVES THIS YEAR...THE NAM MAY HAVE THE
RIGHT IDEA OF CLOSING OFF A WEAK CIRCULATION IN THE GULF.


danielwAdministrator
(Moderator)
Sat Jul 17 2010 12:06 AM
Re: Trough in the Gulf of Mexico

Glad it didn't close off yet. I got 0.79" inches in about 79 minutes from the northern edge of this trough/ wave. It dropped the temp from 98 to 78 degrees in 2 hours. That was nice.
I'm seeing a lot of slow moving thunderstorms on the northern edge of the trough here in Mississippi. Many locations have received 3 to 4 inches or more, since noon today, from nearly stationary storms.
However there doesn't seem to be as much activity along the Coastal areas.


Jasonch
(Weather Watcher)
Sat Jul 17 2010 05:56 PM
Re: Areas being Watched

The caribbean sure is active today, two big areas of disturbed weather.

danielwAdministrator
(Moderator)
Sat Jul 17 2010 07:41 PM
Re: Areas being Watched

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 17 2010

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC...

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS ALONG 49W S OF 19N MOVING W AT 20 KT. THE
WAVE IS FAIRLY WELL ORGANIZED WITH CYCLONIC TURNING COVERING A
BROAD AREA OF ABOUT FIVE DEGREES EITHER SIDE OF THE WAVE AXIS.
THE WAVE IS ALSO EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE
AS DEPICTED ON THE TOTAL PRECIPITABLE WATER ANIMATION. SCATTERED
MODERATE CONVECTION IS ON THE W SIDE OF THE WAVE AXIS FROM
15N-17N BETWEEN 52W-55W.

TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES WITH AXIS
ALONG 64W S OF 17N MOVING W AT 20 KT. A DIFFLUENT PATTERN ALOFT
BETWEEN AN UPPER-LEVEL LOW N OF PUERTO RICO AND A RIDGE OVER THE
EASTERN CARIBBEAN IS HELPING TO INDUCE CONVECTION NEAR THE WAVE
AXIS. SCATTERED MODERATE TO STRONG CONVECTION IS SEEN FROM
13N-18N BETWEEN 62W-69W.

TROPICAL WAVE IS S OF E CUBA ALONG 75W MOVING W AT 15-20 KT.
CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE W OF THE
WAVE AXIS TO INCLUDE JAMAICA AND THE CAYMAN ISLANDS FROM 15N-21N
BETWEEN 75W-82W.
http://www.nhc.noaa.gov/text/refresh/MIATWDAT+shtml/171722.shtml?


MikeCAdministrator
(Admin)
Mon Jul 19 2010 02:47 PM
Re: Areas being Watched

Recon is scheduled for a possible mission out to 97l on Wednesday, depending on how it looks at the time.

There is a possibility that the system stays more south and rides the northern islands, never getting in the straits, this would be bad for Haiti but would keep development chances nonexistent.

There is a lounge topic discussing long range hints, but it's still early.


danielwAdministrator
(Moderator)
Mon Jul 19 2010 04:22 PM
Re: Areas being Watched

Early morning Caribbean Discussion, excerpt.
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
637 AM EDT MON JUL 19 2010

THE CLIMATOLOGICAL MODELS SHOW FAVORABLE MJO CONDITIONS FOR THE
REST OF THE WEEK. THE MORE RELIABLE CLIMATE FORECAST SYSTEM
INDICATES THAT BY THE BEGINNING OF NEXT WEEK WE ARE TO TRANSITION
TO A WEAK CONVERGENT/NEUTRAL PATTERN...WHICH IS TO LAST FOR TEN
DAYS...AND TRANSITIONING AGAIN TO A DIVERGENT PATTERN ALOFT BY THE
FIRST WEEK IN AUGUST.

DISCUSSION FROM JUL 19/0000 UTC.


JoshuaK
(Weather Guru)
Mon Jul 19 2010 08:04 PM
Re: Areas being Watched

There appears to be at least one circulation center near 20.5N and 63.6W as of the 19:15 UTC satellite imagery, hard to tell if it's an Up, Mid, or Low, but it appears to have just started forming within the last few hours, at least from the loop imagery.

WesnWylie
(Weather Guru)
Mon Jul 19 2010 08:05 PM
Re: Wave Northeast of Caribbean Worth Watching this Week

97L looks fairly impressive this afternoon, except I cannot see any type
of spin within the system yet. The buoy reports within this region are falling
steadily; a 3mb drop since 10:50 a.m. CDT is noted on buoy 41043 as of
1:50 p.m. The 12z ECWMF takes this wave to the Central Texas coast by
Saturday afternoon/evening. Although this may be a bit too quick, the track
seems possible. Definitely need to keep an eye on this one, since it could
impact more than one state on the Gulf Coast.

BTW JoshuaK, I see the circulation you noted on the above post. I think it is
either a low-level or mid-level circulation trying to develop but not an upper.


Doombot!
(Weather Guru)
Mon Jul 19 2010 08:23 PM
97L

On the current 97L vis floater there is a thin "wave" of clouds being ejected in the NW quadrant. What phenomenon causes this?


Time sensitive
http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html


Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Mon Jul 19 2010 10:48 PM
Re: 97L

Its called a 'rope' cloud. Its a gust front caused by collapsing convection with a temperature differential strong enough to create condensation. Sometimes seen ahead of a cold front in winter in the subtropics.
ED


Lamar-Plant City
(Storm Tracker)
Tue Jul 20 2010 03:48 AM
Re: 97L

Quote:

Its called a 'rope' cloud. Its a gust front caused by collapsing convection with a temperature differential strong enough to create condensation. Sometimes seen ahead of a cold front in winter in the subtropics.
ED



Nice catch as I just was able to see it on the late satellite. Can't these also be seen on a smaller scale rushing out from under a collapsing thunderstorm? Maybe not as impressive but still the same type of effect? Being in central Fla, I see thin bands of clouds in front of and behind large T-storms. they can also be detected on Doppler radar at times. Same or different?


JoshuaK
(Weather Guru)
Tue Jul 20 2010 07:42 AM
Re: 97L

97L isn't looking too healthy early this morning, with a lot of the convection dying down. In other areas of the Atlantic, there is a cluster of convenction on the southern edge of a Tropical Wave, near 7N 35W that appears, at least to my novice eye, that has some interesting circulation and persistance about it, something in the ITCZ to keep our eyes on at least. The wave itself has a nice spin to it, but is pretty much devoid of any shower activity. Finally, there is a big honking wave about to emerge off of Africa that has a huge blowup of convection as of the latest 6-hour shot from the GOES EastAtl Floater.

Ed in Va
(Weather Master)
Tue Jul 20 2010 12:18 PM
Re: 97L

FWIW, there is a lot more model support now, with a landfall somewhere between N.O. and the Panhandle. Anywehre from a moderate tropical storm to a CAT 1.
http://moe.met.fsu.edu/tcgengifs/

Correction: The GFS actually takes it over the Keys and S. Florida.


WesnWylie
(Weather Guru)
Tue Jul 20 2010 01:46 PM
Attachment
Re: Wave Northeast of Caribbean Worth Watching this Week

97L is actually looking quite healthy this morning in my opinion. Although it is not
as widespread as it was yesterday, the smaller area of convection looks more organized
near the center compared to earlier. I think the NHC has it right with the 40% chance of
development for 97L. I think they will likely bump it to 50% by this afternoon as I think I see
what appears to be the low-level circulation showing up near the northeast tip of Puerto
Rico.


MichaelA
(Weather Analyst)
Tue Jul 20 2010 02:06 PM
Re: 97L

The GFDL, GFS, and HWRF models are all in agreement this AM on a track across So. FL and entering the Gulf between Punta Gorda and the Tampa Bay area and then toward the AL/FL border. NGP takes it farther South and West more toward LA. It's early and the models will change a lot in the next several days. The system demands our attention, though.

MichaelA
(Weather Analyst)
Tue Jul 20 2010 02:11 PM
Re: 97L

That also happens with collapsing thunderstorms here in FL near the west coast during the summer.

danielwAdministrator
(Moderator)
Tue Jul 20 2010 02:41 PM
Re: 97L

Rope Cloud from yesterday.


WesnWylie
(Weather Guru)
Tue Jul 20 2010 04:11 PM
Wave nearing the Yucatan Penninsula

I am looking at the visible satellites, and I think the wave in the Northwest Caribbean may be
trying to organize. The area that I am looking at (as of 15:45) is near 85W and 19N. I am not for
sure, though.


LoisCane
(Veteran Storm Chaser)
Tue Jul 20 2010 04:30 PM
Re: Wave nearing the Yucatan Penninsula

Has a sense of itself....

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

Curvature, bands... all it needs now is a center.

Water temps are not as warm as usual I think in the Bahamas...
it's not just an issue of the models sticking with it... it's more a matter of being able to see it possibly happening on the loops.

Not the best conditions yet... think it's got better than average chances of being something with a name.


Lamar-Plant City
(Storm Tracker)
Tue Jul 20 2010 05:44 PM
Re: Wave nearing the Yucatan Penninsula

So what has happened to cause the NHC to up it to a 60% chance of development in such a short period of time. I admit it looks fairly impressive, but still a lot of very dry air to the north and north west. Not sure when they upped it but I just noticed it.

WesnWylie
(Weather Guru)
Tue Jul 20 2010 05:46 PM
Re: 97L

The NHC has upgraded 97L to a code red (60% chance of development). I think we will probably be tracking a depression by tonight as it continues to organize. It is certainly getting interesting.

MichaelA
(Weather Analyst)
Tue Jul 20 2010 06:06 PM
Re: 97L

The shear has all but vanished over this system. It does look as though it will pull together tonight and tomorrow, but it's proximity to Hispaniola should tend to keep it rather weak in the short term. I'm not seeing a LLC just yet in the vis loop nor on San Juan radar - maybe a slight hint of one forming, but nothing definite just yet. The GFDl now takes it more northward, the GFS is esentially unchanged, and the HWRF splits them on the 12Z runs. Until there is a LLC for several runs, the models don't mean a whole lot. Expect lots of changes in them in the near term.

danielwAdministrator
(Moderator)
Tue Jul 20 2010 06:45 PM
Re: 97L

Could this be the reason??

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
137 PM EDT TUE JUL 20 2010

VALID 12Z FRI JUL 23 2010 - 12Z TUE JUL 27 2010

FINAL...

THE 12Z GUIDANCE CONTINUES TO SHOW A MODERATE DEGREE OF SPREAD
WITH BOTH THE TIMING AND INTENSITY OF SHORTWAVES ALONG THE
CANADIAN BORDER THIS PERIOD. THE LATEST GEFS MEAN AND UKMET ARE
CLOSEST TO THE 00Z ECENS MEAN...USED FOR THE UPDATE PACKAGE...WITH
THIS 12Z GUIDANCE SLIGHTLY FASTER WITH THE PROGRESSION OF POLAR
CYCLONES. THE GFS AND PARALLEL GFS STILL DO NOT CLUSTER WELL
ENOUGH WITH THE BULK OF THE OTHER GUIDANCE TO BE VERY RELIABLE.
CHANGED THE GULF TROPICAL WAVE TROUGH TO A LOW CENTER...AS PER
COORDINATION WITH TPC.
NONE OF THE NEW MODELS DEVELOP THIS SYSTEM
TO A SUBSTANTIAL DEGREE. OTHERWISE...MADE ONLY MINIMAL CHANGES
FOR THE FINAL ISSUANCE.
(emphasis added by danielw)
http://www.srh.noaa.gov/productview.php?pil=PMDEPD&max=61


WesnWylie
(Weather Guru)
Tue Jul 20 2010 07:11 PM
Re: 97L

I think 97L will be a depression by late tonight or tomorrow morning since it continues to organize.
The NHC continues to mention that the only thing missing is a defined low-level circulation, but I
think we will have one soon enough. The latest models have trended south with the system which
is the more likely solution. I think this system has the potential to wind up over the next few days,
especially if it does not move inland over Florida but stays over the water. On accuweather.com,
Joe Bastardi has a good commentary on 97L and he thinks it has the potential to wind up fairly quickly.


MikeCAdministrator
(Admin)
Tue Jul 20 2010 11:42 PM
Re: 97L

There is a fair chance that South Florida/Keys will see Tropical Storm or possibly Hurricane Watches or Warnings sometime Thursday if the storm continues like it is. I'm not sold on intensity wise, but there chances went up enough today to suggest it.

I'd really like it to develop first to go further than that, but... most likely the system will stay just south or at South Florida, as some sort of tropical system. The area may increase, but it's unlikely to be a major storm. I put a little more in the forecast lounge, if you want to make guesses, or discuss the long range models, go over there and check it out.


Jasonch
(Weather Watcher)
Wed Jul 21 2010 12:26 AM
Re: 97L

I know that we have to have a storm to develope before we can get a better idea of what it is going to do and where it is going to go. But can somebody give me some idea of how strong the HIGH Pressure may be and how far west it could go and is the northwestern gulf at risk. After going through Hurricane Rita and Ike in my area both times we were on the edge of the HIGH Pressure system. What was suppose to be a south texas landfall ended up being a south east texas landfall (big difference?)

MikeCAdministrator
(Admin)
Wed Jul 21 2010 12:41 AM
Re: 97L

Right now Texas is very unlikely. Second landfall would most likely be in the north central Gulf or Florida Panhandle, but it looks like conditions may be unfavorable in that area. Too far out to tell, though, it's really Forecast Lounge territory.

WeatherNut
(Weather Master)
Wed Jul 21 2010 01:46 AM
Re: 97L

I'm seeing a lot more rotation in the sat. presentation. and a big blog of convection where the center would be. Also starting to see outflow developing on the west side which tells me shear is decreasing

Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 02:28 AM
Re: 97L

Quote:

I'm seeing a lot more rotation in the sat. presentation. and a big blog of convection where the center would be. Also starting to see outflow developing on the west side which tells me shear is decreasing




Satellite presentation is indeed indicative of a tropical depression at present, in my opinion.

Having said that, I don't think the NHC will pull the trigger until we have visible satellite confirmation, surface observations, or recon confirmation of a LLC. Also, radar imagery from San Juan doesn't confirm the LLC that appears to exist on the satellite loop.


MichaelA
(Weather Analyst)
Wed Jul 21 2010 02:46 AM
Re: 97L

Quote:

I know that we have to have a storm to develope before we can get a better idea of what it is going to do and where it is going to go. But can somebody give me some idea of how strong the HIGH Pressure may be and how far west it could go and is the northwestern gulf at risk. After going through Hurricane Rita and Ike in my area both times we were on the edge of the HIGH Pressure system. What was suppose to be a south texas landfall ended up being a south east texas landfall (big difference?)




The most recent model runs that I looked at all indicate the ridge eroding to the East which would allow a more NW to N track in the later period.


danielwAdministrator
(Moderator)
Wed Jul 21 2010 03:32 AM
Re: 97L

I'm checking the San Juan radar storm velocity product. It appears that a vortice is just offshore of the northern coast of Puerto Rico. Middle of the island and about 20-40 miles north. I'll attach a photo as soon as I get it resized.

NW quadrant of the radar where blue and gold meet. In this location for a two hour duration. Mileage rings place the vortice about 45 miles offshore. This is elevated as the San Juan radar site is in or near the mountains near 3000 feet.. That would place the observed vortice around 4000 to 5000 feet using 0.5 elevation on the radar.



This is the composite reflectivity image at the same time. Convection is co-located with the observed vortice. My opinion only.



Doombot!
(Weather Guru)
Wed Jul 21 2010 03:38 AM
Re: 97L

I see what you're talking about, but that cell in moving NNE. Perhaps just a tornadic supercell?

berrywr
(Weather Analyst)
Wed Jul 21 2010 12:04 PM
Re: Wave Looking Weaker This Morning

Windshear aloft is between 30 and 40 knots...it is highly unlikely we'll see development in the next 24 hours.

MikeCAdministrator
(Admin)
Wed Jul 21 2010 12:37 PM
Re: Wave Looking Weaker This Morning

Based on visible imagery, my best guess of a center is north of the Dominican Republic, around 70.4w 20.5n, but no real low level circulation, if the storm reforms to the east it changes the timeline a bit, but I'm not sure that will happen.

the official position is 70w 20N, which is possible too, but today will be a lot of waiting to see if anything fires up again.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 12:57 PM
Re: Wave Looking Weaker This Morning

I'm looking at the visible loop, and 20N 70W looks pretty close to me, but your positioning is plausible too, Mike. Overall, it looks a bit like somethng took a knife to the whole system overnight. NHC says it's still code red, but down to 60%, and I think that's very generous - but then again, I thought 70% last night was too low. Models haven't shifted southward to correspond to a shallower system, though, which is curious. In fact, models (at 2am, I haven't seen the 8am run yet) are in very disturbing agreement, that ultimate landfall will be in the Florida panhandle, near Ft. Walton Beach. That there is so much agreement this far out is alarming.

Edit: Just went to Skeetobyte, which has the 12z model runs. They all point to the LA/TX border.


WesnWylie
(Weather Guru)
Wed Jul 21 2010 01:58 PM
Re: Wave Looking Weaker This Morning

Looking at the water vapor imagery and visible satellites, it appears to be the upper-level low to its
north that is at this time shearing 97L apart. Until it can distance itself from the low some more, it will
continue having trouble becoming organized. I think that late tonight/tomorrow will be the time it
begins to develop more.
It does look like a landfall somewhere between Houston and New Orleans is increasing since 97L
will likely remain somewhat weak for the next day or so.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 02:08 PM
Re: Wave Looking Weaker This Morning

Well, WU's model page now shows that all of those models have shifted.. northward. But, Skeetobite says those are the 06z models, not the 12z runs (WU says they're from 8am EDT). They barely take it into the GOM at all. Regardless of strength, I don't see this getting west of Louisiana.

rgd
(Weather Hobbyist)
Wed Jul 21 2010 02:51 PM
Re: Wave Looking Weaker This Morning

Quote:

I'm looking at the visible loop, and 20N 70W looks pretty close to me, but your positioning is plausible too, Mike. Overall, it looks a bit like somethng took a knife to the whole system overnight. NHC says it's still code red, but down to 60%, and I think that's very generous - but then again, I thought 70% last night was too low. Models haven't shifted southward to correspond to a shallower system, though, which is curious. In fact, models (at 2am, I haven't seen the 8am run yet) are in very disturbing agreement, that ultimate landfall will be in the Florida panhandle, near Ft. Walton Beach. That there is so much agreement this far out is alarming.

Edit: Just went to Skeetobyte, which has the 12z model runs. They all point to the LA/TX border.






You understand it is not even developed yet so the models are really out to dry till it does to say Florida panhandle is insane.In fact the newer ones have it going north more and up the north coast of Florida.

Until it OR IF it becomes a storm the models are really of little use.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 03:58 PM
Re: Wave Looking Weaker This Morning

Quote:


You understand it is not even developed yet so the models are really out to dry till it does to say Florida panhandle is insane.In fact the newer ones have it going north more and up the north coast of Florida.
Until it OR IF it becomes a storm the models are really of little use.




Yeah, um, if you look RIGHT ABOVE YOUR POST you will see where I posted that the newer models show it barely going into the Gulf.


weathernet
(Storm Tracker)
Wed Jul 21 2010 04:23 PM
Re: Wave Looking Weaker This Morning

Have to agree on the limited benefit that the models provide at this time; at least until a better organized core forms.

No doubt that the upper low to the systems north, is having havoc with the system. Interesting to note however, that satellite presentation of this cold low would seem to indicate that it is warming some. Still, for the time being and in tandum with the inflow to its south being temporarily cut off by Hispanola, conditions for rapid development are just not there. This all said, the system should progress WNW over warmer water and with regeneration of convection over what might at least be a more evident COC north of Hispanola, that a reasonable chance still exists for development into a TS prior to reaching Florida. Good news is that the threat of a worse impact has gone way way down.

Small core systems certainly have the potential to deepen quicker than larger systems especially given high octane fuel ( SST's ). Until we have a developed tropical depression though, that risk becomes that much smaller. Still, plenty of time for things to change for those in the gulf.


MikeCAdministrator
(Admin)
Wed Jul 21 2010 04:24 PM
Re: 97L

The system appears to have been hindered a bit by the dry air, mountains of Hispaniola, and some shear along with the upper level low. It'll reach better conditions gradually through tomorrow, I still think it may develop tomorrow.
Convection is still off, but the overall structure is improving.

South Florida still is the most likely location where it may go, but at most as a Tropical Storm.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 04:56 PM
Re: 97L

Convection seems to be making a bit of a comeback as the day progresses. We'll have to see if it persists or gets sheared again. If recon hadn't been cancelled today, I think they would have had enough evidence to classify this thing as TD Three. It also appears to have gained a considerable amount of latitude, which may put more of the east coast of Florida in the path.

On the other hand, maybe I'm blind,because the NHC actually DOWNGRADED it at the 2pm TWO, to code orange at 50%.


danielwAdministrator
(Moderator)
Wed Jul 21 2010 05:44 PM
Re: 97L

MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
106 PM EDT WED JUL 21 2010

VALID JUL 21/1200 UTC THRU JUL 25/0000 UTC
excerpt~danielw

...TROPICAL WAVE CROSSING CUBA AND THE FLORIDA STRAITS...

THE NAM...UKMET...AND 00Z ECMWF ALL HANDLE THIS SYSTEM COMPARABLY.
THE GFS IS SLOWER...EXTENDING THE INVERTED TROUGH FARTHER NORTH.
THE MIDDAY MEDIUM RANGE COORDINATION WITH TPC RESULTED IN A
FORECAST OF A SURFACE LOW CROSSING THE NORTHWEST CORNER OF THE
GULF OF MEXICO DAY 3.


?? Northwest corner on Day 3. Should that be NE Corner??~danielw

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
837 AM EDT WED JUL 21 2010

VALID 12Z SUN JUL 25 2010 - 12Z WED JUL 28 2010
excerpt

THE PRESSURES STARTED WITH A BLEND OF THE 00Z CANADIAN/06Z GFS
PARALLEL...BEFORE SWITCHING TO A 06Z GFS PARALLEL/00Z ECMWF
ENSEMBLE MEAN COMPROMISE AFTER MONDAY MORNING WHICH MAINTAINS
REASONABLE CONTINUITY. MINOR ADJUSTMENTS WERE THEN MADE TO
ENHANCE DEFINITION... AND TO YIELD A COMPROMISE FCST BETWEEN
FARTHER NORTHEASTWARD CONTINUITY VERSUS THE MAJORITY OF LATEST
ENSEMBLE AND DETERMINISTIC GLOBAL GUIDANCE WITH THE TROPICAL
DISTURBANCE FORECAST TO MOVE THROUGH THE GULF OF MEXICO EARLY IN
THE PERIOD. A PERSISTENTLY STRONG SOUTHEASTERN RIDGE ALOFT ALONG
WITH VERIFICATION OF RECENT FEATURES FORECAST OVER THE GULF OF
MEXICO DO NOT APPEAR TO SUPPORT THE RECURVATURE SCENARIO INTO THE
CENTRAL/EASTERN GULF COAST FAVORED BY POINTS MENTIONED ON THE 16Z
NHC/MEDIUM RANGE COORDINATION CALL YESTERDAY...HENCE THE SOUTHWEST
ADJUSTMENT. A PERSISTENT LACK OF ECMWF ENSEMBLE SUPPORT FOR THIS
SYSTEM CALLS INTO QUESTION HOW STRONG OF A FEATURE WILL ACTUALLY
MATERIALIZE IN THE GULF OF MEXICO FROM THIS DISTURBANCE.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 05:52 PM
Re: 97L

If I read that the way it's written it sounds like it says the system will head to Texas (NW Gulf) as opposed to "recurving" towards Florida.

MichaelA
(Weather Analyst)
Wed Jul 21 2010 05:59 PM
Re: 97L

I'm beginning to have doubts that this system will develop into anything significant - nothing more than an open wave or, at most, a TD. The 12Z GFDL works a weak system crossing FL, 12Z GFS shows only an open wave moving through the FL Straights, and the HWRF seems to be a bit overly aggressive in its 12Z run. The next 24 hours will either confirm my suspicions or something miraculous will happen.

Storm Hunter
(Veteran Storm Chaser)
Wed Jul 21 2010 06:27 PM
Attachment
Re: 97L

the NW part of GOM should be the NW part of GOM... Typo error by HPC.

See attachment done by TPC for 72hr forecast


Evan Johnson
(Weather Guru)
Wed Jul 21 2010 06:38 PM
Re: 97L

anyone notice the flare up @ 70, 22?

Doombot!
(Weather Guru)
Wed Jul 21 2010 06:40 PM
Re: Wave Looking Weaker This Morning

I'm going againts the grain here, but I'm seeing both a return of a CDO feature with rotation around it. If this trend continues, I would think code red at 8PM and TD at 11PM.

MichaelA
(Weather Analyst)
Wed Jul 21 2010 06:44 PM
Re: Wave Looking Weaker This Morning

I don't see a LLC and the mid-level circulation is West of the convection indicating a high shear environment continues to exist over the system. I still don't see this developing in the short term.

B_from_NC
(Verified CFHC User)
Wed Jul 21 2010 06:55 PM
Re: Wave Looking Weaker This Morning

Certainly has a LLC. Its just south of the Turks.

1KM Loop

Convection is starting to flare around the LLC but with the shear it will be hard pressed to make it around. Still a waiting game. Has a lot of negative for the next 24 hours or so.


Evan Johnson
(Weather Guru)
Wed Jul 21 2010 07:07 PM
Re: Wave Looking Weaker This Morning

Quote:

Certainly has a LLC. Its just south of the Turks.

1KM Loop

Convection is starting to flare around the LLC but with the shear it will be hard pressed to make it around. Still a waiting game. Has a lot of negative for the next 24 hours or so.




yeah there is barely a low level circulation, but its there, well visible in that loop.


doug
(Weather Analyst)
Wed Jul 21 2010 08:30 PM
Re: Wave Looking Weaker This Morning

It appears that the ULL is moving out to the WNW a little quicker than 97L is moving WNW. That should permit a anti-cyclonic upper flow to begin to enhance ventilation and potential development. Tomorrow is the key. If there is no closed low tomorrow then the chances of a classified system developing before it closes on South Florida are greatly diminished. That does not mean that storm type conditions would not effect the lower half of the peninsula Friday-
Saturday, however.


MikeCAdministrator
(Admin)
Wed Jul 21 2010 10:10 PM
Re: Wave Looking Weaker This Morning

Quote:

It appears that the ULL is moving out to the WNW a little quicker than 97L is moving WNW. That should permit a anti-cyclonic upper flow to begin to enhance ventilation and potential development. Tomorrow is the key. If there is no closed low tomorrow then the chances of a classified system developing before it closes on South Florida are greatly diminished. That does not mean that storm type conditions would not effect the lower half of the peninsula Friday-
Saturday, however.




There is still no low level circulation is correct, if one were to form tomorrow it would probably be right near or just south of the Caicos islands in the Caicos Bank. But the make or break will be tomorrow. This area has spawned a few notable storms in the past (including the formation of TD#10 in 2005), but not really in July.

It has on more night of shear (tonight) to survive before conditions improve tomorrow. The upper level low is moving out toward the west now, away from the system.. If it makes it through relatively intact tonight then it has a real shot for development tomorrow. Track wise it's still seems south Florida/straits is the odds favorite, again deepening if it develops tomorrow or not. If it doesn't develop tomorrow, chances drop off greatly it will this side of Florida.


MikeCAdministrator
(Admin)
Wed Jul 21 2010 10:22 PM
Re: Wave Looking Weaker This Morning

A new area (98L) Is being tracked in the Bay of Campeche, this was the wave mentioned earlier in the week in the NHC outlook that was in the West Caribbean at the time. 20.0N 92.8W



berrywr
(Weather Analyst)
Wed Jul 21 2010 10:32 PM
Re: Wave Looking Weaker This Morning

Good afternoon! The strong tropical wave as expected has become more disorganized as upper winds are not favorable for development. Surprisingly with the lone exception of San Juan there was no mention of the TUTT low...upper level cutoff low and shortwave just to the north and immediate west of the tropical wave. It is this ULL that has resulted in the wave becoming weak. There is considerable subsidence on the back side of the shortwave extending from this ULL.

The 12Z model package all all unanimous in this wave not closing off and it continuing west and west-northwest across FL in 24 to 36 hours and into the GOM tracking west to the TX/KA coast in 72 to 96 hours as the upper ridge over the SE USA stengthens and extends into the Atlantic with east to west flow across the Gulf states and FL.

A purely tropical depression/storm is out of the question for the near term, though one cannot rule out a hybrid.

There continues to remain the possibility that beyond this forecast window and the wave enters the GOM that the upper air will be more conducive for development.

An area I've been looking at is the huge plume of tropical moisture on water vapor satellite over the western GOM extending south to the Yucatan. That said, I haven't looked at that region in depth or pressures at the surface to comment in depth.


berrywr
(Weather Analyst)
Wed Jul 21 2010 10:38 PM
Re: Wave Looking Weaker This Morning

I just made a comment about that entire area and I like it's chances than the wave north of Hispanola. If that area does develop into something it is only a threat to TX and MX...the ridge over the SE USA will prohibit it from moving anywhere near the northern gulf and points east. I'll know more when the 00Z package comes out tonight and I take an indepth look at the upper air package tonight,

A word of caution....if the wave over Hispanola remains a shallow...these two areas will likely merge at some point beyond 48 hours. It is impossible at this time to say how the two interacting with one another if there is any level of development of either or both.


berrywr
(Weather Analyst)
Wed Jul 21 2010 10:56 PM
Re: Watching Two Systems

As I've commented on the other thread concerning the system over Hispanola...this area bears watching...Mike's right! A quick look...I'll comment more later on this system...it doesn't appear that this particular system will be over water long enough for anything to come of it and models depict the TUTT to the north to move west under the upper ridge which in turn would depict a west movement to this disturbance. This is the third system this season. It should be added that there has been some sort of upper level low, east coast longwave trough over the Western Atlantic for a good part of the season which is right up Ed's alley.

WesnWylie
(Weather Guru)
Wed Jul 21 2010 11:13 PM
Re: Watching Two Systems

97L appears to be organizing once again. It seems to be shaking that pesky upper-low to some extent since the upper-low is outrunning the speed at which 97L is moving. It will be interesting to see what the models show in just
a little while; at this time, I think a landfall between Biloxi, Mississippi and Houston, Texas seems more likely than earlier due to 97L's delayed development.

I don't know just yet, as far as where 98L will go, but I figure North Central Mexico is the most likely place. Of course, with no model runs on 98L yet, my guess could be wrong.


Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 11:20 PM
Re: Watching Two Systems

It (97L) is still not the most organized system I've ever seen, but... if there's no LLC, I'm blind.
Convection is, once again, beginning to build over the "non-existent" LLC, in fact. We'll see what the NHC
says in 30 minutes or so, but I would think it would be bumped back up to code red again. It actually looks very close to depression status right now, but I said the same thing 24 hours ago.

update: 8pm TWO is out, and I'm obviously blind.


allan
(Weather Master)
Wed Jul 21 2010 11:37 PM
Re: Watching Two Systems

After looking at the CIMMS shear map, shear is already relaxing over 97L (currently 10-20 knots) as the ULL is moving fairly quickly to the west, and away from the invest. The NHC will probably keep percentages at 50%. Though tonight into tomorrow, there will be a battle for the spotlight! 98L will probably start with a code orange 30-40% on the next TWO do to the conditions it's in and the organized feature it is. I won't be surprised to see Bonnie and Colin in the Atlantic tomorrow, this would shut an end to a quite start. Most Julys get up to about B or C for average.

Hugh
(Senior Storm Chaser)
Wed Jul 21 2010 11:45 PM
Re: Watching Two Systems

They put 97L at 40% and 98L at 30% (both code orange). The TWO actually said that 97L was "disorganized"?

k___g
(Weather Guru)
Wed Jul 21 2010 11:48 PM
Re: Watching Two Systems

I don't see that happening...too much negative influence on all of these systems.

WesnWylie
(Weather Guru)
Thu Jul 22 2010 12:47 AM
Re: Watching Two Systems

The early 00z round of models shows a landfall centered on Louisiana similar to what I mentioned in my previous post. Still awaiting the model runs on 98L... so will update and comment more as soon as they do .

None of the models take 98L near the U.S. coast, so no worries there .


Hugh
(Senior Storm Chaser)
Thu Jul 22 2010 01:06 AM
Re: Watching Two Systems

So much for "it's not going to Texas" I guess. Until it forms, models are junk.

WesnWylie
(Weather Guru)
Thu Jul 22 2010 03:57 AM
Attachment
Re: Watching Two Systems

I have attached an infrared satellite image of 97L as of 0340. It looks to me that it is now in the process of trying to close off a low-level circulation. It helps if you play the loop from the link below. I think the NHC will up the chance for development from a code orange to a code red by the 8:00 a.m. EDT update, and that we will have a tropical depression tomorrow. I don't care for the Louisiana/Texas landfall that most of the models are painting, but we do need the rain in our area, just not the wind. Tomorrow will be the decider whether 97L will be something to closely monitor or not.

http://aviationweather.gov/adds/satellit...ig&itype=ir


berrywr
(Weather Analyst)
Thu Jul 22 2010 05:11 AM
July 22-00Z Model Package - Invest 97L

Good evening and early morning! The NHC downgraded from 70 percent to 40 percent the probability of 97L becoming a tropical depression.

Tonight there is an upper level low between 850 and 500 mbs located almost directly over the disturbance and an upper low at 300 and 200 mbs over the Northern Bahamas. NHC sampled extensively the area this evening and reported wind shear and dry air as the primary causes as to why the wave has not developed.

This upper level low is not vertically stacked as depicted at various levels this evening and the overall system has moved very little over the past 12 hours and appears to have deepened as water vapor imagery clearly shows an elongated north to south upper level low.

This ULL has resulted in wind shear aloft between 30 and 40 knots directly to the west of the system and continues to impact the system tonight.

There is strong thunderstorm activity underneath the upper level low but that is not unusual nor is it uncommon for depressions to develop under an upper level low.

I see nothing on tonight's upper level analysis and 21/18Z model run to suggest this system will develop into something serious though the track is through the oil slick and to LA.

The axis of the wave is right along this axis of dry/moisture axis and as long as this persists; 97L will remain a wave.

Conclusion....I cannot rule out this system may become a depression, but it's going to be slow and it's going to be in a hostile environment. It will have a better opportunity to develop once west of FL and the ULL leaves itself of the area.


berrywr
(Weather Analyst)
Thu Jul 22 2010 05:17 AM
Re: July 22-00Z Model Package - Invest 98L

Invest 98L continues to organize and is a better candidate to become a tropical depression. That said, the upper air environment will drive this system directly into the NE MEX coast and is no threat to the United States.

There is an upper ridge directly over Alabama this evening and will continue to build over the Atlantic Ocean with Invest 97L and inverted upper level shortwave/low moving west and west-northwest under the ridge with models depicting LA as "landfall." These two features will force 98L northwest.

The good news...the system won't be over water long enough to become serious.


MichaelA
(Weather Analyst)
Thu Jul 22 2010 10:33 AM
Re: July 22-00Z Model Package - Invest 97L

Very good analysis. That is the same thing I've been seeing with 97L over the last two days. I'm looking forward to some rain and slightly "cooler" weather here this weekend. If 97L is to pull itself together at all, it will be in the GoM.

MichaelA
(Weather Analyst)
Thu Jul 22 2010 02:00 PM
Re: July 22-00Z Model Package - Invest 97L

Well, I was certainly wrong on that call. We'll see how this progresses from here.


Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center