| cieldumort |
| (Moderator) |
| Sun Oct 21 2012 03:14 AM |
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Sandy Forecast Lounge
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A tropical wave nestled within a very large area of lower sea level pressure is tracking west through the Caribbean this weekend, and is in an area increasingly favorable environment for development. This feature has been tagged as Invest 99L, and NHC now gives it a 60% chance of becoming a tropical cyclone within 48 hours.
Invest 99L has an excellent blueprint for development, and this system has the potential to become a tropical cyclone that undergoes rapid intensification, which could take many by surprise heading into the new week.
In the lower levels, the circulation is already pretty well defined, with the blueprint for future spiral banding solidly in place. In the upper levels, winds are very light, and increasingly anticyclonic. Throughout the column, the air is moist, and relatively free of the dry air intrusions which have plagued so many other tropical features this season.
As of 3:00 AM Sunday October 21, 99L was centered near 15N 75W, with maximum sustained winds estimated at around 30 MPH.
This is where to put long range best guesses on intensity and forecast track. Long range model output discussions are also appropriate here.
At present, models are basically unanimous in developing Invest 99L within the next three days, but are very split with regard to its future track.
danielw
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| (Moderator) |
| Sun Oct 21 2012 07:55 AM |
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Re: Invest 99L Forecast Lounge
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Roughly 6 hours later. You can see the slight changes in 99L
| LoisCane |
| (Veteran Storm Chaser) |
| Sun Oct 21 2012 09:01 AM |
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Re: Invest 99L Forecast Lounge
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What is most impressive in ways is how suddenly out of nothing... comes something.
It's been so quiet in the tropics and most waves have been weak, poorly formed and odd looking.
Here we suddenly have (as the models predicted) a well organized wave with rudimentary spiral banding features and the right shape, in the right place with conditions positive for intensification.
Begs you to think on the possibilities, despite my cautious mind that says it will just go NE out of the Caribbean. But, a lot depends on WHEN it forms and the exact place that surface circulation begins as to the timing of the exact real track.
Good job by the models of seeing this even when they were 15 days out.
| ftlaudbob |
| (Storm Chaser) |
| Sun Oct 21 2012 05:05 PM |
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Re: Brewing Up Two More Invests
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The models have changed.The east coast of Florida now needs to watch this close.Could have an impact by the end of this week.99l I am referring to.
(Post moved to a more appropriate Forum.)
| MichaelA |
| (Weather Analyst) |
| Sun Oct 21 2012 06:41 PM |
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Re: Invest 99L Forecast Lounge
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With all of the models being in relatively good agreement this early on, before a surface system even forms, is quite interesting to me. Usually, there is a large divergence among them at this stage. Of course, a 100 mile "error" could make a world of difference.
| doug |
| (Weather Analyst) |
| Sun Oct 21 2012 07:32 PM |
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Re: Invest 99L Forecast Lounge
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I agree. It is also unusual that it would exit the Carribean heading NE and then essentially head north up 76W. The future track depends on the relative strength of high pressure exiting off SE conus.
| ftlaudbob |
| (Storm Chaser) |
| Sun Oct 21 2012 10:25 PM |
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Re: Invest 99L Forecast Lounge
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Not much excitement about 99l,I think this may change in a few days.
| WeatherNut |
| (Weather Master) |
| Mon Oct 22 2012 11:22 AM |
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Re: Invest 99L Forecast Lounge
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Well its now been classified as TD18. It is looking much more impressive and the parameters are there for rapid intensification. All of S Fl really needs to keep watch on this now...as well as up the east coast of the CONUS. Its quite telling that they didnt even wait for the recon. Jamaica under a TS Watch
| bobbutts |
| (Weather Hobbyist) |
| Mon Oct 22 2012 12:24 PM |
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Re: Invest 99L Forecast Lounge
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Watching this one from up in New Hampshire
If you haven't looked, check out some of the exotic solutions from the last few days model runs.
| MichaelA |
| (Weather Analyst) |
| Mon Oct 22 2012 05:19 PM |
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Re: Invest 99L Forecast Lounge
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Now, TS Sandy @ 5PM EST
| ftlaudbob |
| (Storm Chaser) |
| Mon Oct 22 2012 05:20 PM |
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Re: Invest 99L Forecast Lounge
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We now have Sandy,not moving at all right now.
| WeatherNut |
| (Weather Master) |
| Mon Oct 22 2012 08:11 PM |
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Re: Invest 99L Forecast Lounge
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Yes some of the models have a pretty nasty looking scenario for the NE and mid Atlantic. JB has been really bullish on the scenario for the last couple of days as well. I dont buy the out to sea like the GFS has quite yet.
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Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Mon Oct 22 2012 08:38 PM |
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Re: Sandy Forecast Lounge
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The 22/12Z ECMWF takes a strong storm (subtropical?) into the northeast whereas the 22/18Z GFS keeps the system well out at sea. In both cases its in the far extended range of 7 to 10 days. So far this year the GFS has been the better performing model, but for now its probably more important to concentrate on the more immediate track of the next few days - especially with regard to Jamaica, Haiti, eastern Cuba and the Bahamas. Wind and flooding impacts will be important in those areas as well as the southeast U.S. coastline (high seas, strong rip currents and possibly beach erosion). Looks like the latest forecast track has slowed the forward motion down a bit and that could allow for a stronger storm to develop.
ED
| LoisCane |
| (Veteran Storm Chaser) |
| Mon Oct 22 2012 09:20 PM |
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Re: Sandy Forecast Lounge
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I'm curious how TD 19 and Sandy interact or how if possible 19 can help steer Sandy out to sea or the opposite. So many complex things going on. How strong this front is? How fast is this front? Late October is a very difficult time to forecast such a complex tropical set of scenarios.
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danielw
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| (Moderator) |
| Tue Oct 23 2012 12:08 AM |
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Re: Sandy Forecast Lounge
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The 12Z Experimental FIM really winds Sandy up. Looks to be a hybrid after crossing Cuba, skirts the Bahamas with 25 to 30 mph sustained winds along the southern half of the Florida Atlantic Coast, moves NE and then bombogenesis begins north of 30 degrees North latitude.
I think I saw a 925 to 930mb level at 336 hours, or Nov 5th.
Perfect Storm, Part Two? We shall see.
| ftlaudbob |
| (Storm Chaser) |
| Tue Oct 23 2012 12:21 AM |
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Re: Sandy Forecast Lounge
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I am hearing more and more talk about the "perfect storm" ,should be very interesting.
| cieldumort |
| (Moderator) |
| Tue Oct 23 2012 03:33 AM |
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Re: Sandy Forecast Lounge
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Trying to remember the last time (if ever) I have read a Forecast Discussion that called for a tropical cyclone to be "Subtropical" at Day 5 (instead of the usual "Post-Tropical," or "Extratropical," or "Dissipated"). Looks like NHC is giving some heavy consideration to model runs that do indeed show a strong possibility of a 'Perfect Storm.'
BY 120 HOURS...SANDY IS EXPECTED TO
INTERACT WITH A DEEP UPPER-LEVEL TROUGH THAT COULD INDUCE
TRANSITION INTO A SIGNIFICANT SUBTROPICAL CYCLONE. THE OFFICIAL
INTENSITY FORECAST IS HIGHER THAN THE PREVIOUS ADVISORY THROUGH 48
HOURS...AND CLOSELY FOLLOWS A BLEND OF THE ICON...IV15...IVCN
INTENSITY CONSENSUS MODELS.
FORECAST POSITIONS AND MAX WINDS
INIT 23/0300Z 12.7N 78.6W 40 KT 45 MPH
12H 23/1200Z 13.6N 78.4W 50 KT 60 MPH
24H 24/0000Z 14.8N 77.9W 60 KT 70 MPH
36H 24/1200Z 16.6N 77.5W 70 KT 80 MPH
48H 25/0000Z 18.5N 77.1W 60 KT 70 MPH...INLAND OVER JAMAICA
72H 26/0000Z 22.7N 75.8W 55 KT 65 MPH...OVER WATER
96H 27/0000Z 25.7N 75.4W 55 KT 65 MPH
120H 28/0000Z 28.2N 73.6W 55 KT 65 MPH...SUBTROPICAL
| Owlguin |
| (Weather Hobbyist) |
| Tue Oct 23 2012 08:38 AM |
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Re: Sandy Forecast Lounge
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Seems as though the models have shifted a little west this morning.
| doug |
| (Weather Analyst) |
| Tue Oct 23 2012 09:30 AM |
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Re: Sandy Forecast Lounge
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Interesting it is now the GFS that jogs the storm briefly westward toward the peninsula as it slows in the Bahamas, before turning it ENE and out to sea. ECMWF, takes this system off shore up the coast line as a significant NE'r. NHC is closer to the GFS without the jog.
| doug |
| (Weather Analyst) |
| Tue Oct 23 2012 04:41 PM |
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Re: Sandy Forecast Lounge
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Confidence in the track ends at five days...several of the models in the FSU ensemble have a very strong low center essentially plaguing the entire eastern coast line of the US after that...ECMWF takes the low center ashore in New England. Yikes!
GFS has it out to sea...
No reliable handle on the strength of the trough coming from the west, I guess.
| Joeyfl |
| (Weather Guru) |
| Tue Oct 23 2012 07:01 PM |
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Re: Sandy Forecast Lounge
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Sandy looks to be a menace or a downright historic storm possibly for the eastern U.S. Its alarming to me that the European which continue to advertise a significant storm recurving NW into the Northeast next week. After really scratching my head and seeing a track like that is quite rare if at all, but its does have support from the Nogaps,GEM, and GFS ensemble members. Its interaction with the Omega block consisting of a blocking high in the north Atlantic, and a large ocean storm over the central north Atlantic, and a digging negatively tilted upper trough over the Ohio valley will be critical in determining where Sandy goes. But Iam starting to think Sandy may miss her chance out to the northeast like GFS says with it undercutting the block. Time will tell but I would watch this very very closely!
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MikeC
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| (Admin) |
| Tue Oct 23 2012 11:06 PM |
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Re: Sandy Forecast Lounge
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The coastal beach erosion/flooding setup for the east coast (of Florida and possibly north) is going to be much worse than usual if this system rapidly converts to subtropical/post tropical. It's not out of the realm of possibility to see 20-25 ft seas Friday off east central Florida, which will translate into a ton of beach erosion in areas not usually accustomed to it. Probably higher than it's been in decades by Friday (It's slowly already gaining now)
| ftlaudbob |
| (Storm Chaser) |
| Tue Oct 23 2012 11:09 PM |
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Re: Sandy Forecast Lounge
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The seas here are already very rough.About 60% of beach is covered now.Pretty windy all day.
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MikeC
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| (Admin) |
| Tue Oct 23 2012 11:23 PM |
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Re: Sandy Forecast Lounge
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Posting the marine discussion from Miami tonight, bolding the important parts.
MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
250 PM EDT TUE OCT 23 2012
MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA
AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W.
...
SW N ATLC S OF 31N W OF 65W...
SHEARLINE MENTIONED ABOVE COMBINING WITH HIGH PRES TO THE NNW TO
PRODUCE A BROAD ZONE OF 20-25 KT WINDS AND SEAS TO 8 FT NE OF
THE N HALF OF BAHAMAS AND THROUGH THE STRAITS OF FLORIDA...WHILE
FRESHENING EASTERLIES TO THE S WILL CONTINUE TO INCREASE AS
SANDY DEEPENS NEXT 24-36 HOURS. SANDY OF MAIN FOCUS OF FORECAST.
HIGH PRES WILL REMAIN N AND NW OF SANDY AS IT EXITS CARIBBEAN
NEXT 48 HOURS AND COMBINE WITH MONSOONAL ORIGINS TO PRODUCE VERY
LARGE WIND FIELD SHIFTING NNE WITH SANDY. CURRENT NELY FETCH N
OF SHEAR LINE ALREADY YIELDING 6-8 FT SEAS NE OF BAHAMAS AND 5-6
FT ALONG THE FLORIDA COASTS. VERY DANGEROUS SCENARIO IS
DEVELOPING WITH SANDY AS SUFFICIENTLY SLOW MOVEMENT...PRE
EXISTING HIGH SEAS...VERY LARGE WIND FIELD...AND ONSHORE FLOW
DURING HIGH LUNAR TIDES COULD SPELL EXTREME COASTAL FLOODING AND
EROSION FOR FLORIDA AND CERTAINLY BAHAMAS WED NIGHT THROUGH SAT.
WW3 FORECASTING 12 FT SEAS TO REACH CENTRAL FLORIDA COAST BY 18Z
THU WITH SEAS BUILDING 20-35 FT WITHIN THE COASTAL WATERS BY 18Z
FRI. THIS COULD EVOLVE INTO A HISTORICAL EVENT AND FO'S ARE
ENCOURAGED TO ADVERTISE THIS EVENT VERY HARD. NELY SWELL WILL
CONTINUE TO IMPACT FLORIDA AND SE COASTS THROUGH THE WEEKEND
WITH LONGER PERIOD SWELL INDUCING SUSTAINED RUNUP.
| WeatherNut |
| (Weather Master) |
| Wed Oct 24 2012 11:05 AM |
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Re: Sandy Forecast Lounge
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Well its now been upgraded to a Hurricane. I think the out to sea option is becoming very unlikely. The GFS has been trending west and the Euro has remained consistent that an epic storm will strike in the Long Island area. The storm surge alone would be devastating. The GFS now has Sandy going out but develops another storm which rides up the coast. Bottom line for those in NYC and all areas around it should monitor this situation closely...VERY closely as nobody has seen anything close to this (if it verifies) in our lifetimes
Pressure has dropped 8mb in less than an hour as messured by recon
| Joeyfl |
| (Weather Guru) |
| Wed Oct 24 2012 02:56 PM |
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Re: Sandy Forecast Lounge
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Another day has gone by since my last post with myself leaning very closely to the European solution with a chance of this being an event to remember. Its a hard to think that this could be a historic or dare I say storm of the century type but it is quite possible. I really think this is also going to be rough squally storm for FL east coast with winds of strong TS force possibly hurricane gusts especially from near the Cape and points south as the storms wind field expands. Beach erosion will likely be severe not just for FL but large area of the eastern seaboard. Time will tell but this storm has the makings to being one that unfortunately maybe one we never forget.
| Troy C |
| (Verified CFHC User) |
| Wed Oct 24 2012 05:10 PM |
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Re: Sandy Forecast Lounge
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This reminds me of the Halloween Storm of 1991. Some refer to that as the Storm of the Century.
Very possible wave event similar to that..
(Post moved from the Storm Forum to the appropriate Forum.)
| WeatherNut |
| (Weather Master) |
| Wed Oct 24 2012 05:26 PM |
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Re: Sandy Forecast Lounge
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This wont be just a FL storm...they will get wind and some rain and thunderstorms. Its looking more and more like this is a bigger threat between the Delmarva and Cape Cod with historic snowfalls in WV for this time of year
| WeatherNut |
| (Weather Master) |
| Wed Oct 24 2012 05:30 PM |
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Re: Sandy Forecast Lounge
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What the euro is suggesting is a similar situation, however, the storm of 1991 (Grace was the tropical part) never came on shore. It went up the coast and out. If this come onshore from the SE it would bring big storm surges at astronomical high tide (full moon). It would push surge up the river valleys as well.
(Post moved from the Storm Forum to the appropriate Forum.)
| jkapust |
| (Registered User) |
| Wed Oct 24 2012 06:00 PM |
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Re: Sandy Forecast Lounge
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Well it is finally up, a hazardous weather outlook including sandy, in the Boston area. I was wondering how long it would take for those to be posted, all the while the NHC track still does not include the west turn as expected by many of the spaghetti models and gfs ensemble members.
WHILE DEPENDENT ON THE TRACK...THERE IS GREATER CONFIDENCE FOREARLY NEXT WEEK OF A POST-TROPICAL SANDY MAKING EITHER A CLOSE
PASS /STRONG WINDS...HIGH SEAS...POSSIBLE COASTAL FLOODING AND
ISOLATED POWER OUTAGES/...OR A DIRECT HIT ON SOUTHERN NEW ENGLAND
/HURRICANE FORCE WINDS WITH DOWNED TREES AND WIDESPREAD POWER
OUTAGES...HIGH SEAS AND STORM SURGE RESULTING IN BEACH EROSION
AND COASTAL FLOODING...AND FINALLY HEAVY RAINS RESULTING IN
INTERIOR FLOODING/.
Fortunately the latest gfs ensemble members are beginning to look less spread from Maine to the Maryland and more south of Boston, where I reside. Storms in new england are exciting. Looking forward to tracking this one.
(Post moved to the appropriate Forum.)
| Joeyfl |
| (Weather Guru) |
| Wed Oct 24 2012 06:46 PM |
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Re: Sandy Forecast Lounge
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Sandy is really looking impressive now with a very nice CDO and eye. She looks to be getting stronger and Jamaica has no effect on her, a good sign that this storms structure is well organized and strong. I dont see any reason why this will not be 90-100mph cane at landfall in Cuba. Recon will also have the obstacle of the no fly over in Cuba but will be able to get some measurements before reaching Cuba later this evening. There is know doubt that Sandy will be a serious problem for the eastern seaboard with tides already above normal with full moon Monday is just going to make for a significant coastal flooding and if the deeper Euro verifies anywhere close to what it is projecting (950-960mb!) it will be a storm I think of historic proportions. So much warm air will be pulled in that the only real snow threat will be in the central Appalachians.
| doug |
| (Weather Analyst) |
| Wed Oct 24 2012 08:24 PM |
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Re: Sandy Forecast Lounge
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The models are the most interesting I have seen in quite a while..The arrival and the relative depth of the forecasted strong trough from the west must be difficult to get a handle on...The most reliable have Sandy doing an elongated S up the coast. A couple have it feignt to the NW and get it as close the Florida as Grand Bahama...if t is transitioning at that time the windfield will expand and gales in many parts of Florida could result, along with the terrible erosion of most of the coast line...yeah this could be very interesting.
Glad the west coast of Florida will remain in the fringes...
| WeatherNut |
| (Weather Master) |
| Wed Oct 24 2012 08:27 PM |
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Re: Sandy Forecast Lounge
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Structure has improved quite a lot
CI# /Pressure/ Vmax
5.4 / 956.8mb/ 99.6kt
Final T# Adj T# Raw T#
5.4 6.4 6.5
Those T and CI #'s are definitely in Cat2-3 territory
| ftlaudbob |
| (Storm Chaser) |
| Thu Oct 25 2012 01:37 AM |
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Re: Sandy Forecast Lounge
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Great looking hurricane now,eye is clearly seen.Seas here are really building.Where should I post current condition's?Should have some really good video on Friday from the beach?
| cieldumort |
| (Moderator) |
| Thu Oct 25 2012 02:09 AM |
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Re: Sandy Forecast Lounge
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Sandy is pretty much a major hurricane heading into its first landfall, and it doesn't look likely that its track over Cuba will interrupt it in a very meaningful way, such that by the time it comes closer to Florida the opportunity for some impressive video will definitely be there. Please share Sandy conditions in your area here.
| ftlaudbob |
| (Storm Chaser) |
| Thu Oct 25 2012 03:04 AM |
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Re: Sandy Forecast Lounge
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A rare sight,an eye over mountains.Talk about holding together.
| ftlaudbob |
| (Storm Chaser) |
| Thu Oct 25 2012 03:47 AM |
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Re: Sandy Forecast Lounge
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It is half way across Cuba and the eye is very much intact.Even over the mountains,this storm is very healthy.Amazing,look at this. http://www.ssd.noaa.gov/goes/east/tatl/vis.jpg
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danielw
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| (Moderator) |
| Thu Oct 25 2012 07:05 AM |
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Re: Sandy Forecast Lounge
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Latest, 00Z FIM model takes Sandy through the Bahamas on the western side of the Islands, crosses Grand Bahama at the bend and begins moving northeastward. Maintains a near constant distance offshore until Sandy moves ashore in Maine.
Different, nearly 180 degree change in forecast since I last posted.
Could spell more than trouble with the cold air moving into New England.
| Random Chaos |
| (Weather Analyst) |
| Thu Oct 25 2012 07:32 PM |
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Re: Sandy Forecast Lounge
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Ok, what is with these crazy MSLP's near landfall? GFDL is bombing to a 925mb asymmetrical system near the NJ coast. Other models are getting close to that, though I don't have precise numbers.
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MikeC
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| (Admin) |
| Thu Oct 25 2012 07:41 PM |
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Re: Sandy Forecast Lounge
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The 18Z GFS model is crazy, and along the lines of the Euro. There is a possibility once the upper level low presence is gone for Sandy to re-intensify and possibly be nudged a bit west (RAP shows Bimini islands in the Bahamas... It won't actually get that far west, but it may be a bit west of where it is now, perhaps to around 150 miles offshore Florida), so tomorrow and Saturday will probably be nasty along the Florida coastline. The system is heading a bit more north northwest now than it was earlier.
GFS was the only one (until late yesterday) holding out for an out to sea scenario in the Northeast. That deep pressure drop is sure troubling, even if it doesn't verify to that degree, the impact will still be huge in the northeast.
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MikeC
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| (Admin) |
| Thu Oct 25 2012 08:09 PM |
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Re: Sandy Forecast Lounge
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The 18Z GFDL stalls it off Cape Hatteras and deepens the storm to 929mb, and then flings it around into the Chesapeake.
| Random Chaos |
| (Weather Analyst) |
| Thu Oct 25 2012 09:19 PM |
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Re: Sandy Forecast Lounge
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That run is really bad for me. It's still the southern outlier, so hopefully it shifts back north. For the Chesapeake, if the storm comes on the east/north side of the bay, it blows the water out of the bay. If the storm comes on the west/south side, it blows water into the bay. So the best option for minimizing flood damage is for the storm to stay to the east as long as possible, allowing the water level to lower from the prevailing winds and preventing substantial coastal flooding.
| Random Chaos |
| (Weather Analyst) |
| Thu Oct 25 2012 09:33 PM |
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Re: Sandy Forecast Lounge
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Relevant blog post about a past storm: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=304
| berrywr |
| (Weather Analyst) |
| Thu Oct 25 2012 09:41 PM |
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Re: Sandy Forecast Lounge
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Just got home from a day of college classes...so, stay tune...the fun is just getting started for the New England area...please do not forget that the wind field is likely to be huge so concentrating on a specific landfall is mute in fact the strongest winds are likely to be well away from the center due to a tight surface pressure gradient and a robust upper air to include a polar jet.
| berrywr |
| (Weather Analyst) |
| Thu Oct 25 2012 09:43 PM |
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Re: Sandy Forecast Lounge
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The following is the Final Extended Forecast Discussion out of the HPC...the same website which includes a current and out to 7 day surface analysis -
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
313 PM EDT THU OCT 25 2012
VALID 12Z SUN OCT 28 2012 - 12Z THU NOV 01 2012
...HIGH IMPACT MERGING OF ENERGETIC SYSTEMS ANTICIPATED OFF THE
MID ATLANTIC COAST...
PRELIMINARY UPDATE...
DESPITE A MODEST CLUSTER OF OUTLYING DETERMINISTIC SOLUTIONS AND
ENSEMBLE MEMBERS FROM THE VARIOUS MODELING CENTERS, THE LION'S
SHARE OF GUIDANCE INDICATES THAT THE CIRCULATION ASSOCIATED WITH
HURRICANE SANDY WILL PASS CLOSE ENOUGH TO THE AMPLIFYING POLAR
TROUGH OVER THE EASTERN UNITED STATES TO BECOME INCORPORATED INTO
A HYBRID VORTEX OVER THE MID ATLANTIC AND NORTHEAST NEXT TUESDAY.
THE HIGH DEGREE OF BLOCKING FROM EASTERN NORTH AMERICA ACROSS THE
ENTIRE ATLANTIC BASIN IS EXPECTED TO ALLOW THIS UNUSUAL MERGER TO
TAKE PLACE, AND ONCE THE COMBINED GYRE MATERIALIZES, IT SHOULD
SETTLE BACK TOWARD THE INTERIOR NORTHEAST THROUGH HALLOWEEN,
INVITING PERHAPS A GHOULISH NICKNAME FOR THE CYCLONE ALONG THE
LINES OF "FRANKENSTORM", AN ALLUSION TO MARY SHELLEY'S GOTHIC
CREATURE OF SYNTHESIZED ELEMENTS.
AS IS OFTEN THE CASE, WHEN ONE PART OF THE NATION IS EXPERIENCING
A VERY ENERGETIC ATMOSPHERE DISTURBANCE, THE REMAINDER IS
RELATIVELY CALM. THIS EVENT SHOULD NOT PROVE THE EXCEPTION, WITH A
FAIRLY BENIGN FEED OF PACIFIC AIR INTO MOST OF THE WESTERN AND
CENTRAL STATES. THE FAR WEST, PARTICULAR NORTH OF CALIFORNIA, WILL
HAVE ENOUGH SUSTAINED ONSHORE FLOW TO KEEP THE PERIOD WET AND
UNSETTLED.
FINAL...
UPDATED THE TRACK OF SANDY TO FIT THE 15Z/25 NATIONAL HURRICANE
CENTER TRACK THROUGH 5 DAY, WHICH DOVETAILS WELL INTO THE HYBRID
LOW POSITIONS THEREAFTER FOR DAYS 6 AND 7. BOTH THE 12Z/25 GFS AND
GEM GLOBAL BRING THE LOW INTO THE NEW YORK CITY AREA, WITH THE
ECMWF DIRECTING IT INTO THE LOWER DELMARVA PENINSULA. THE UPSHOT
FOR SENSIBLE WEATHER IS THE SAME- HIGH WINDS AND HEAVY RAINS FOR
AREAS ALONG THE TRACK OF THE TROPICAL REMNANT, WITH HEAVY SNOWS
POSSIBLE ON THE SOUTHWEST EDGE WHERE THE CONTINENTAL POLAR AIR
RUSHES ACROSS THE UPPER OHIO VALLEY AND CENTRAL APPALACHIANS AND
ADJACENT LOWLANDS TO THE EAST.
CISCO
| Random Chaos |
| (Weather Analyst) |
| Thu Oct 25 2012 11:43 PM |
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Re: Sandy Forecast Lounge
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One thing that concerns me is inland flooding potential. In the case of the 18Z GFS run, this is in MD, VA, NJ, and southern PA. The GFS 18Z run is predicting landfall on the NJ coast, moving inland, then sitting for nearly 36 hours nearly stationary somewhere in either northern MD or southern PA, sucking in huge amounts of tropical moisture and dumping it. I don't trust the total precip predictions since they usually underperform tropical systems; these predictions are showing 3-5" of rain for this region. For 36 hours under the center of a tropical or subtropical cyclone, that seems low.
| Random Chaos |
| (Weather Analyst) |
| Fri Oct 26 2012 12:46 AM |
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Re: Sandy Forecast Lounge
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Interesting developments with a couple recent models shifting landfall back north. What I am seeing is a gyre off the mid-atlantic coast seen in CMISS wind analysis. This gyre affects shallow systems mostly, with less affect on deep systems. What looks to be occurring is oscillations in how deep the models are forecasting the system to be when it starts interacting with the gyre (the point at which the eastward turn occurs, and NE movement starts). The result is directly related to how far out into the Atlantic Sandy gets before it turns back into the trough. In the case with current models (such as the 00Z GFS), a weaker, shallower Sandy is pushed further into the Atlantic resulting in a landfall near New York city. In comparison, the ECMWF and the GFDL are forecasting a deeper system, causing less affect from the gyre and resulting in a more southerly landfall, possibly even southern MD or into VA.
I think over the next 12-24 hours we will have a much better handle on the landfall location - the depth of the storm and it's interaction with this gyre will be very evident once it starts to make its turn to the NE.
| Random Chaos |
| (Weather Analyst) |
| Fri Oct 26 2012 06:32 AM |
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Re: Sandy Forecast Lounge
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NRL is showing huge wind radii just prior to landing:
http://www.nrlmry.navy.mil/TC.html
Gale force winds extend the equivalent distance from the great lakes south to the gulf coast about 12 hours before landfall, and TS winds about half that distance. That impacts the entire Atlantic coastline from Massachusetts south to Florida. Beware beach erosion.
Also, 06Z GFS is now looping the storm just offshore of the Delmarva and NJ beaches before slamming it into NY. That's even worse for beach erosion than a quick hit. It's the only model doing that, though.
| ftlaudbob |
| (Storm Chaser) |
| Fri Oct 26 2012 01:52 PM |
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Re: Sandy Forecast Lounge
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Looks to me like dry are from the south is pushing into Sandy and really hurting this storm.
http://www.ssd.noaa.gov/goes/east/watl/flash-wv.html
| berrywr |
| (Weather Analyst) |
| Fri Oct 26 2012 04:31 PM |
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Re: Sandy Forecast Lounge
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Sandy has run out of time in regards to doing anything else as a tropical system...the upper level is ringing her doorbell over on the water vapor imagery. The folks over at NHC have some really cool toys to determine if her core is warm core through and through; I hope for the public's sake that Sandy is designated Subtropical early on...hearing snow and a hurricane in the same sentence is simply weird; subtropical...bring it! Clearly Sandy is undergoing structural changes that began last night. I will look at everything in detail later tonight but we married boys have a saying; a happy life is a happy wife...see y'all tonight!
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MikeC
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| (Admin) |
| Fri Oct 26 2012 07:37 PM |
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Re: Sandy Forecast Lounge
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This is the period of wait and see now, as it weakens and gets sheared, before the full baroclinic conversion takes place (when it will likely deepen again) is going to be a lot of wait and see.
For those in the Northeast, be prepared for outages, especially in the coastal areas (But likely fairly far inland). There are quite a few unknowns with this system since there have been so few in history to take a path and conversion like Sandy is forecast to.
Folks from the east Carolinas through Maine need to pay close attention as the wind field for Sandy (or whatever it becomes) will cover a vast area.
| HobbyistinNH |
| (Verified CFHC User) |
| Fri Oct 26 2012 07:51 PM |
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Re: Sandy Forecast Lounge
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Quote:
This is the period of wait and see now, as it weakens and gets sheared, before the full baroclinic conversion takes place (when it will likely deepen again) is going to be a lot of wait and see.
For those in the Northeast, be prepared for outages, especially in the coastal areas (But likely fairly far inland). There are quite a few unknowns with this system since there have been so few in history to take a path and conversion like Sandy is forecast to.
Folks from the east Carolinas through Maine need to pay close attention as the wind field for Sandy (or whatever it becomes) will cover a vast area.
I just shared this in the other lounge, but will share here
This is from Cocoa Beach FL.
Any liklihood of this hitting MA or SNH? I don't know what models are doing...
| ftlaudbob |
| (Storm Chaser) |
| Fri Oct 26 2012 10:18 PM |
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Re: Sandy Forecast Lounge
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This has a very good chance of being the weather event of our lifetimes.Never before have we seen this happen.I hope everyone one in the North East is prepared for an extremely bad situation.Very scary. Three systems coming together at the same time,wow.
| HobbyistinNH |
| (Verified CFHC User) |
| Fri Oct 26 2012 10:45 PM |
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Re: Sandy Forecast Lounge
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Quote:
This has a very good chance of being the weather event of our lifetimes.Never before have we seen this happen.I hope everyone one in the North East is prepared for an extremely bad situation.Very scary. Three systems coming together at the same time,wow.
The Jet Stream, The Hurricane, and what else.
I could not find the "third system"
| ftlaudbob |
| (Storm Chaser) |
| Fri Oct 26 2012 11:29 PM |
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Re: Sandy Forecast Lounge
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There is a storm coming from the west,a strong arctic blast coming from the north and of course Sandy.
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danielw
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| (Moderator) |
| Sat Oct 27 2012 12:45 AM |
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Re: Sandy Forecast Lounge
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506
FXUS02 KWBC 261827
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
226 PM EDT FRI OCT 26 2012
VALID 12Z MON OCT 29 2012 - 12Z FRI NOV 02 2012
...DANGEROUS HURRICANE/POST-TROPICAL CYCLONE SANDY IS LIKELY TO
SPREAD HIGH WINDS/HEAVY RAINS AND INTERIOR HEAVY SNOWS FROM THE
CAROLINAS AND CENTRAL APPALACHIANS NORTHWARD INTO CANADA...
GENERAL FLOW PATTERN
====================
A RETROGRADING POSITIVE ANOMALY MOVING FROM SOUTHERN GREENLAND
INTO NORTHERN QUEBEC FAVORS A QUASI-STATIONARY DEEP CYCLONE NEAR
THE NORTHEAST, IN THIS CASE HURRICANE SANDY AND ITS POST-TROPICAL
REMAINS. OTHERWISE...RIDGING IS GENERAL EXPECTED OUT
WEST...THOUGH FLOW ACROSS THE PACIFIC IS EXPECTED TO SEND AMPLE
ENERGY/HEAVY PRECIPITATION ACROSS THE NORTHWEST. GUIDANCE IS IN
EXCELLENT AGREEMENT ON THE GENERAL FLOW PATTERN, THOUGH ISSUES
REMAIN WITH SANDY'S FUTURE COURSE AND STRENGTH.
MODEL PREFERENCE
================
THE NATIONAL HURRICANE CENTER (NHC) TRACK NOW BEST RESEMBLES THE
00 UTC ECMWF ENSEMBLE MEAN. THE EXTRATROPICAL TRANSITION OF SANDY
MAY HAVE ALREADY BEGUN BASED UPON RECENT SATELLITE IMAGERY...A
PROCESS EXPECTED TO COMPLETE TUESDAY PER NHC. THE DETERMINISTIC
GUIDANCE (PARTICULARLY THE 00 UTC ECMWF) SHOW PRESSURE SOLUTIONS
WELL BEYOND WHAT HAS EVER BEEN OBSERVED NEAR THE NEW JERSEY/NEW
YORK COAST (EVEN EXCEEDING THE 1938 LONG ISLAND EXPRESS HURRICANE)
EARLY IN THE MEDIUM RANGE PERIOD. THE DETERMINISTIC GUIDANCE
(CANADIAN, GFS, AND ECMWF INCLUDED) HAS SHOWN A VERY STRONG BIAS
WITH TROPICAL CYCLONES GAINING LATITUDE AND/OR TRANSITIONING INTO
NON-TROPICAL STORMS OVER THE PAST COUPLE YEARS... INCLUDING (BUT
NOT EXCLUSIVE TO) LESLIE 2012...ISAAC 2012...DEBBY 2012 IN THE
WESTERN SUBTROPICAL ATLANTIC IRENE 2011 AND IGOR 2010. PLEASE
REFER TO THE NHC FOR UPDATED INFORMATION ON SANDY.
THE 00 UTC ECMWF ENSEMBLE MEAN ALSO DEPICTS AN OVERALL FLOW
PATTERN UPSTREAM ACROSS THE W-CENTRAL CONUS AND ERN PACIFIC THAT
IS ON THE MORE AMPLIFIED AND LESS PROGRESSIVE SIDE OF THE FULL
ENVELOPE OF GUIDANCE SOLUTIONS OVER THE NEXT WEEK. THIS SEEMS
QUITE REASONABLE CONSIDERING DOWNSTREAM BLOCKING.
WEATHER IMPACTS
===============
PER THIS SOLUTION FROM SUNDAY THROUGH WEDNESDAY...WINDS AS HIGH AS
HURRICANE-FORCE ARE EXPECTED TO LASH EXPOSED AREAS OF THE
NORTHEAST/MID-ATLANTIC STATES (THE COAST AND TOPOGRAPHY)...LEADING
TO POTENTIALLY SERIOUS COASTAL EROSION AND COASTAL FLOODING. THE
TIMING OF THE FULL MOON AND THE BUILD-UP OF TIDES OVER MULTIPLE
TIDAL CYCLES SHOULD EXACERBATE THE SITUATION ALONG THE
COAST...PARTICULARLY IN CORNERS SUCH AS THE NEW YORK BIGHT. HEAVY
RAINS ARE EXPECTED TO FOCUS WITHIN SANDY'S WARM CONVEYOR BELT
CIRCULATION AS WELL AS ALONG ITS DRAPING WARM FRONT FROM THE
NORTHERN MID-ATLANTIC STATES AND INTO NEW ENG AND ERN
CANADA...WITH LOCAL AMOUNTS EXCEEDING 10 INCHES POSSIBLE. THIS
SOLUTION WOULD MEANWHILE ALLOW SIGNIFICANT SNOWS WITHIN ITS COMMA
HEAD PATTERN UNDER THE SUPPORTING/COOLING MID-UPPER LEVEL TROUGH
TO FALL AS CENTERED/FOCUSING OVER THE CENTRAL THEN NRN
APPALACHIANS AND VICINITY. LAKE EFFECT SNOWS ACROSS THE EASTERN
GREAT LAKES ARE POSSIBLE THROUGH THE PERIOD WITHIN THE CYCLONIC
FLOW IN THE SYSTEM'S COLD SECTOR. AS THE CYCLONE GRADUALLY WEAKENS
AS IT PULLS NORTHWARD THURSDAY INTO NEXT FRIDAY...WINDS SHOULD
SLACKEN AS SHOULD NERN US PRECIPITATION AMOUNTS/COVERAGE...BUT
EXPECT THAT AMOUNTS WILL REMAIN SIGNIFICANT CONSIDERING TROPICAL
ORIGIN OF THE LOW.
UPSTREAM...A SOLUTION CLOSEST TO THE 00 UTC ECMWF ENSEMBLE MEAN
SLOWS FROM HPC CONTINUITY SLIGHTLY THE INLAND PROGRESSION OF ERN
PACIFIC SYSTEM ENERGY ACROSS THE WRN US MID-LATE NEXT WEEK...MORE
SLUGGISH TO BUMP INTO A LEAD AMBIENT MEAN MID-UPPER RIDGE
POSITION. THIS SOLUTION OFFERS STRONG POTENTIAL FOR HEAVY
PRECIPIATION/MOUNTAIN SNOWS ACROSS MUCH OF THE NWRN US NEXT
WEEK...INCLUDING THE THREAT FOR MEDIUM RANGE DAYS 4-7 LIQUID
AMOUNTS UPWARDS TO 5 INCHES OVER MOST FAVORED PAC NW COASTAL
TERRAIN AND THE CASCADES...WITH DECREASING BUT STILL WIDESPREAD
AMOUNTS SPREADING FURTHER INLAND.
ROTH/SCHICHTEL
$$
bold emphasis added~danielw
| Random Chaos |
| (Weather Analyst) |
| Sat Oct 27 2012 10:48 AM |
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Re: Sandy Forecast Lounge
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I have learned from previous storms: never discount the GFDL. As the storm gets closer, the other models are getting closer to what the GFDL has been forecasting for the two days - a more southern hit, somewhere in Deleware (or a little south) or southern NJ. GFS is still a northern outlier, while the ECMWF and other major models are getting much closer to the current GFDL.
The GFDL itself has shifted a bit north from a pair of runs two days ago, but except for those two runs which were southern outliers (near the mouth of the Chesapeake), it is surprisingly close to the same track for the past two days.
And now for the bad part: The GFDL track has it crossing the Chesapeake Bay (east to west, thankfully! not south to north!) about 6 miles north of me. Yuck.
| Random Chaos |
| (Weather Analyst) |
| Sat Oct 27 2012 11:01 AM |
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Re: Sandy Forecast Lounge
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ECMWF Ensemble at 2100 hours on 10-29-12 - most likely Deleware Bay area hit:
http://twitpic.com/b7vs70
So right now the cone of the top models goes from central/southern New Jersey to about the Maryland/Deleware line. The inland track is more interesting as some of the models make the system "loop" as far south as southern VA over a 1-2 day period, while others have it quickly turn north after a couple hours.
| HobbyistinNH |
| (Verified CFHC User) |
| Sat Oct 27 2012 01:19 PM |
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Re: Sandy Forecast Lounge
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The track is changing... or tracks..
How worried should we be here in NH?
Is it likely to take a sharp turn towards PA or remain in the waters??
Either way with those 3 storms, we're pretty much screwed and should get prepared right??
I just worry. Last year with Irene we went all out, and boarded up windows, and stocked up.
But PSNH sent an email cautioning us to get prepared. It is my understanding this is a one time event of a lifetime?
CURRENT CONDITIONS FOR MANCHESTER, NH
Mostly Cloudy 65°
Wind: NNE at 4
Humidity: 61%
Dewpoint: 51°
Pressure: 30.06 in
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danielw
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| (Moderator) |
| Sat Oct 27 2012 02:24 PM |
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Re: Sandy Forecast Lounge
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At this time, 2:20 pm EDT, the tracks have come into better agreement and it appears that Sandy will landfall somewhere in New Jersey. Somewhere from North New Jersey, GFS Model to Southern New Jersey, Euro model. I may have the models mixed up, but you can still get the picture.
Your area in New Hampshire should get wind and rain. Just check your local NWS Forecast and that's your best bet.
This is a very unusual Storm and some of the wind and rain forecasts will be a bit off. But if you plan for more rain and higher wind speeds you should be okay.
Don't spend valuable time looking at Sandy moving mile by mile. Get all of you Storm Preparations completed and then you can watch Sandy.
This is a mixed post and not totally a Forecast post.~danielw
| mcgowanmc |
| (Weather Hobbyist) |
| Sat Oct 27 2012 02:27 PM |
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Re: Sandy Forecast Lounge
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Hello.
First off, from the sources I'm tracking, no one is prepping
for this. Yes, some are of course, but I don't see anything like
20 million.
Not one tv shot of plywood going up.
" Post subject: Re: ATL: SANDY - Hurricane - Discussion
PostPosted: Sat Oct 27, 2012 12:24 pm
Online
Category 5
Category 5
User avatar
Joined: Mon Apr 10, 2006 3:10 pm
Posts: 3889
This is shaping up to be a monster. I have friends up at NYU, I have been warning them about this since Tuesday, and last night they said people still aren't preparing. I've been telling them to get their kits ready and prep for evacuation if necessary. These are going to be a historic couple of days.
Second, I've been looking at a Stall since Tuesday.
Now in the Clark and Skeetobite Ensembles, too many models
have Sandy looping and lasting at least 120 hours.
I'm looking at one 168 hr total near Scranton.
Philly and Baltimore to Pittsburgh.
Record warmth in the Gulf Stream. Major Evaporation.
20 in rain and 2 ft snow.
This will be the first 'Climate Change Anthropocene We're Here Storm'.
| Random Chaos |
| (Weather Analyst) |
| Sat Oct 27 2012 05:40 PM |
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Re: Sandy Forecast Lounge
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This was in my local NWS forecast office (LWX / Sterling VA) forecast discussion:
ONE...HIGH WINDS WILL BE A BIG ISSUE...WITH SUSTAINED WINDS RANGING
FROM 30 TO AS HIGH AS 45 MPH WITH GUSTS TO 60 MPH. SEE GRIDDED
FORECAST FOR DETAILS. OF COURSE...JUST WHERE WINDS WILL CRASH
DOWN WILL BE DEPENDENT ON SANDY/S TRACK AND HOW THE TRANSITION TO
AN EXTRATROPICAL STORM OCCURS. ALSO...WITH FORECAST 850 HPA 80-110
KT WINDS ADVERTIZED IN THE MODELS...HOW MUCH/WHEN THESE WINDS MIX
DOWN IS DIFFICULT TO PIN DOWN. THESE WINDS ARE JUST AMAZING IN
TERMS OF THEIR HIGH SPEED. I CANNOT RECALL EVER SEEING MODEL
FORECASTS OF SUCH AN EXPANSIVE AREAL WIND FIELD WITH VALUES SO
HIGH FOR SO LONG A TIME. WE ARE BREAKING NEW GROUND HERE.
Ref: http://forecast.weather.gov/product.php?...p;highlight=off
(Emphasis added)
| Random Chaos |
| (Weather Analyst) |
| Sat Oct 27 2012 11:40 PM |
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Re: Sandy Forecast Lounge
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Current northern Chesapeake Bay forecast synopsis:
- Peak surge will be early Monday (+1 foot) and late Tuesday (+2 foot)
- Western bay will have a negative surge late Monday into early Tuesday (-0.5 foot)
- Eastern bay will have a positive surge during that same period (+0.5 foot)
- Wind direction will shift from NNE early Monday to N Monday to NW late Monday to W Tuesday.
- Wave height will build to 3-4' on Sunday, 4-5' on Monday, 6-7' on Monday night. Waves will start to decrease Tuesday.
Key point: Highest waves will occur as the wind shifts to the NW and the negative surge begins. By the time the positive surge resumes, winds will be out of the W. This means portions of the western Bay may escape the worst of the coastal damage, but the eastern Bay will not, as both the winds and the positive surge will coincide for them. This is the best case scenario with the storm traveling north of the Bay, through southern PA. If the storm were to shift South, conditions will be much worse.
Sources:
Bay wave height: http://forecast.weather.gov/MapClick.php?lat=39.1123920088853&lon=-76.33580608398438
Surge height: http://www.opc.ncep.noaa.gov/et_surge/et_surge_info.shtml
Wind direction forecast: http://tidesandcurrents.noaa.gov/ofs/cbofs/cbofs.html
Please note that this is general guidance and to plan for worst case scenarios of major coastal damage from surge plus waves.
--
I have lived on the northern Bay for the past 18 years and I have never seen a storm bring 7' waves. During Nor'easters, we commonly get 3-4' waves, rarely any more than that. This storm is unreal.
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danielw
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| (Moderator) |
| Sun Oct 28 2012 12:23 AM |
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Re: Sandy Forecast Lounge
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If Mike and Ed will allow me some latitude here. I'm going to continue to post Forecast Discussions due to the Critical nature of the Hurricane Sandy/ FrankenStorm event.
I'm not sure how many readers that we may have in the Region. But I feel the information is there to be relayed on to the general public that might not receive it otherwise.
FXUS01 KWBC 272101
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
500 PM EDT SAT OCT 27 2012
VALID 00Z SUN OCT 28 2012 - 00Z TUE OCT 30 2012
...A DANGEROUS STORM IN HURRICANE SANDY LURKS OFF THE EAST COAST...
...A QUASI-STATIONARY BOUNDARY SHOULD FOCUS SCATTERED SHOWERS UP
THE APPALACHIAN MOUNTAIN CHAIN AND INTO UPSTATE NEW YORK.
...STEADY ONSHORE FLOW WILL KEEP CONDITIONS UNSETTLED ACROSS THE
NORTHWESTERN CONUS...
OF COURSE THE MAJOR STORY THROUGH MONDAY IS HURRICANE SANDY WHICH
HAD BEEN UPGRADED TO SUCH A STATUS EARLIER THIS MORNING. THE OUTER
BANDS OF HEAVY RAINFALL CONTINUE TO STRADDLE THE COASTAL CAROLINAS
WHERE SEVERAL ADDITIONAL INCHES WILL BE POSSIBLE DURING THE NEXT
COUPLE OF DAYS. THE NATIONAL HURRICANE CENTER EXPECTS THIS SYSTEM
TO MAINTAIN ITS CATEGORY 1 RATING THROUGH MONDAY WHILE GENERALLY
TRACKING TOWARD THE NORTH. BY MONDAY EVENING...HURRICANE SANDY IS
FORECAST TO TAKE A HARD TURN TO THE LEFT IN RESPONSE TO AN
APPROACHING UPPER TROUGH ACROSS THE SOUTHERN/CENTRAL APPALACHIANS.
SUCH A TRAJECTORY WOULD ALLOW THE SYSTEM TO MAKE LANDFALL NEARLY
PERPENDICULAR TO THE COASTLINE SOMEWHERE NEAR CENTRAL NEW JERSEY.
AS EXPECTED WITH ANY TROPICAL DISTURBANCE...HEAVY RAIN...STRONG
WINDS...AND SUFFICIENT STORM SURGE WILL BE POSSIBLE NEAR THE
SYSTEM. BUT WHAT MAKES SANDY DIFFERENT IS THE FACT IT WILL
INTERACT WITH AN UPPER TROUGH TO ITS WEST WHICH SHOULD ULTIMATELY
INVIGORATE THE CYCLONE AND FURTHER EXPAND ITS VAST WIND FIELD. IN
ADDITION...LANDFALL SHOULD OCCUR DURING THE FULL MOON STAGE OF THE
LUNAR CYCLE WHICH FAVORS HIGHER THAN AVERAGE TIDES. CURRENTLY IT
APPEARS MUCH OF THE I-95 CORRIDOR WILL BE SIGNIFICANTLY IMPACTED
BY THIS COMPLEX SYSTEM. OVERALL...THE MID-ATLANTIC AND
NORTHEASTERN U.S. SHOULD STAY UP TO DATE WITH THE LATEST NATIONAL
HURRICANE CENTER FORECAST AT www.NHC.NOAA.GOV.
A FRONTAL BOUNDARY WHICH HAD BEEN MARCHING THROUGH THE MISSISSIPPI
VALLEY AND INTO THE GREAT LAKES HAS QUICKLY COME TO A HALT. THE
BLOCKING PATTERN SETTING UP ALONG THE EASTERN U.S. WITH SANDY
BOUNDED BY AN UPPER RIDGE TO THE NORTH WHICH WILL ALLOW THIS
FRONTAL SYSTEM TO MAINTAIN A NORTH-SOUTH ORIENTATION FROM UPSTATE
NEW YORK DOWN THE APPALACHIAN MOUNTAIN CHAIN. LOW-LEVEL
CONVERGENCE SHOULD GRADUALLY WEAKEN AS WINDS BEGIN RESPONDING TO
HURRICANE SANDY. HOWEVER...ENOUGH UPSLOPE FLOW SHOULD LEAD TO
LIGHT TO MODERATE PRECIPITATION. BY MONDAY...ENOUGH COLD AIR WILL
SPILL DOWN TO EXPERIENCE A CHANGE OVER TO SNOWFALL ACROSS THE
SOUTHERN/CENTRAL APPALACHIANS. UP TO A HALF A FOOT OF SNOW IS
CURRENTLY BEING FORECASTED THROUGH MONDAY EVENING BY THE HPC
WINTER WEATHER DESK.
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danielw
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| (Moderator) |
| Sun Oct 28 2012 01:20 AM |
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Re: Sandy Forecast Lounge
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PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
441 PM EDT SAT OCT 27 2012
VALID 00Z SUN OCT 28 2012 - 00Z WED OCT 31 2012(edited~danielw)
DAYS 2 AND 3...
...CENTRAL/SOUTHERN APPALACHIANS...
THE FCST IS STILL HIGHLY UNCERTAIN WITH THE TRACK OF SANDY AND ITS
INTERACTION WITH THE CLOSED LOW DEVELOPING OVER THE APPALACHIANS.
GUIDANCE INDICATES A SURGE OF TROPICAL MOISTURE ADVECTING INTO THE
MID-ATL REGION AND WRAPPING AROUND THE INTENSE CYCLONE.
THE MODELS ALL SHOW ENOUGH ANOMALOUS LOWERING OF HEIGHTS WITH
STRONG DYNAMIC COOLING TAKING PLACE FOR TEMPERATURES TO BECOME
COLD ENOUGH FOR HVY SNOWFALL ACROSS THE CENTRAL AND SRN
APPALACHIANS LATE SUN INTO TUE. THE INITIAL SNOWS LATE SUN INTO
MON MORNING WILL OCCUR ACROSS THE TERRAIN NEAR THE NC/TN BORDER
INTO AREAS NEAR THE KY/VA BORDER. THIS IS WHERE THE GUIDANCE
SHOWS THE MAX COLD ADVECTION AND WHERE 850 MB TEMPERATURES DROP
BELOW FREEZING. NWRLY FLOW DEVELOPS AND PRODUCES SNOW IN TERRAIN
FACING THE FLOW. AS SUN NIGHT PROGRESSES THE AREA OF COLDER TEMPS
EXPENDS NORTH ACROSS WV AND RAIN CHANGES TO SNOW. AS A
RESULT...THE PROBABILITY UNCERTAINTIES REVOLVE AROUND THE
PRECIPITATION TYPE AND DURATION OF SNOW. ON MON
AFTERNOON/NIGHT... TREMENDOUS NWRLY UPSLOPE FLOW WILL INUNDATE THE
CENTRAL APPALACHIANS FOR HVY WET SNOW ACROSS HIGHER ELEVATIONS OF
WV/EASTERN KY/WESTERN VA AND NEAR THE NC/TN BORDER.
SIGNIFICANT APPALACHIANS SNOWFALL IS LIKELY BUT A WIDE VARIABILITY
PERSISTS ON ACCUMULATIONS AMONG THE MODEL AND ENSEMBLE SOLUTIONS.
POTENTIAL EXISTS FOR 2-3 FEET OF SNOW IN PARTS OF THE HIGHER
CENTRAL APPALACHIANS.
SNOW ACCUMULATIONS AWAY FROM THE TERRAIN MAY DEVELOP TUE AS
HEIGHTS/TEMPS GRADUALLY FALL. THE 12Z NAM HAD THE COLDEST TEMPS
OFF ALL SOLUTIONS AND WAS DISCOUNTED IN FAVOR OF THE 09Z SREF
MEAN/12Z GEFS MEAN/00-12Z ECMWF/12Z UKMET/12Z GFS/12Z GEFS MEAN.
THIS MAJORITY CLUSTER OF SOLUTIONS WAS USED FOR QPF/TEMPERATURE
PROFILES TO DERIVE SNOWFALL PROBABILITIES.
THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.
PETERSEN
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danielw
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| (Moderator) |
| Sun Oct 28 2012 01:29 AM |
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Re: Sandy Forecast Lounge
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MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
111 AM EDT SUN OCT 28 2012
VALID OCT 28/0000 UTC THRU OCT 31/1200 UTC
HURRICANE SANDY
===============
PREFERENCE: 00Z GFS/12Z ECMWF COMPROMISE BY DEFAULT
THE 12Z ECMWF & 00Z GFS MODELS ARE CLOSEST TO THE NATIONAL
HURRICANE CENTER (NHC) TRACK OVER THE NEXT FEW DAYS. STANDARDIZED
ANOMALIES AT THE 500 HPA LEVEL WITH SANDY ARE EXTREME FROM THE
GET-GO, RUNNING A RARELY-SEEN SIX SIGMAS BELOW AVERAGE NEAR THE
30TH PARALLEL AT THE INITIAL TIME STEP, STRONGLY SUGGESTING A
RECORD EVENT IS UNDERWAY. A COMPROMISE OF THE TWO WILL LEAD TO A
REASONABLE COMPROMISE ALOFT, WHERE THE 00Z GFS HAS MUCH LOWER 500
HPA HEIGHTS (ON THE ORDER OF 5220 METERS) THAN THE REMAINDER OF
THE GUIDANCE (THOUGH ITS STANDARDIZED ANOMALIES NEAR ITS CENTER IN
MARYLAND AND PENNSYLVANIA REMAIN WITHIN FOUR SIGMAS OF NORMAL FOR
LATE OCTOBER SO IT CANNOT BE DISMISSED), INCLUDING THE NAM WHICH
CAN BIAS IN THE DEEP DIRECTION. CONSULT LATEST NHC
ADVISORIES/DISCUSSIONS FOR FURTHER INFO REGARDING SANDY.
...MODEL TREND GRAPHICS AT
www.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...
...500 MB FORECASTS AT www.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...
ROTH
$$
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 01:49 AM |
|
Dodge MA and NH?
|
Okay, I am not sure what to believe track wise here.
It looks like it is going to dodge MA and NH all together.
Earlier, around 2-4pm yesterday NH was within the cone.
Now were not.
Should we be prepping for wind, rain, snow and ice as the weather says? I'm just not sure what to believe here or what to expect with her.
Weather conditions have been stable here. Nice breeze, not sure if its attributed to Sandy, doubtful, but it has been fairly clear all day. I guess its a watch, wait and see here.
| berrywr |
| (Weather Analyst) |
| Sun Oct 28 2012 03:46 AM |
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Re: Dodge MA and NH?
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It is imperative that many who contribute to the forums here be made aware that "Hurricane" Sandy is a hybrid cyclone. All the "traditional" rules do not apply to this cyclone. Currently Sandy's center is 385 ENE of Charleston, SC, 275 SSE of Wilmington, NC and yet strong tropical storm/gale warnings are being experienced along the Mid-Atlantic Coast. Sandy is a hurricane but her intensity is not guided by tropical "latent" heat processes; it is being sustained by upper level difluence...which is why there is this huge upper level "exhaust"...we associate tropical cyclones with upper ridges above them...not here...We're looking a very small "tropical" cyclone with convection on the NW side near the surface center and aloft what many of us associate with cold core upper oceanic lows. I'm not going to say there won't be an inner wind maximum...that's possible...but this event will include an outer wind maximum which can be what traditionally are called "hurricane force" wind warnings...there's storm warnings...50 knots...and then there are hurricane force storm warnings...65 knots...the entire NE seaboard can expect 50 to 65 knots not just one small area near the "eye" or "center" of the cyclone. Whether the center moves over your area is mute...your area will be impacted. There is no Central Dense Overcast; no eye, no inner eye core; this is an animal all to itself different and worse, it won't be going anywhere fast...there is an upper ridge over extreme eastern Canada...this cyclone's normal track is blocked, worse, this is a Negative Atlantic Oscillation upper high...very high heights aloft given the latitude of this upper high; it alters major weather patterns. We do not know if this is a 2012 version of the 1991 Perfect Storm or other hybrid weather events we've seen in past years.
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 03:59 AM |
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Re: Dodge MA and NH?
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Quote:
It is imperative that many who contribute to the forums here be made aware that "Hurricane" Sandy is a hybrid cyclone. All the "traditional" rules do not apply to this cyclone. Currently Sandy's center is 385 ENE of Charleston, SC, 275 SSE of Wilmington, NC and yet strong tropical storm/gale warnings are being experienced along the Mid-Atlantic Coast. Sandy is a hurricane but her intensity is not guided by tropical "latent" heat processes; it is being sustained by upper level difluence...which is why there is this huge upper level "exhaust"...we associate tropical cyclones with upper ridges above them...not here...We're looking a very small "tropical" cyclone with convection on the NW side near the surface center and aloft what many of us associate with cold core upper oceanic lows. I'm not going to say there won't be an inner wind maximum...that's possible...but this event will include an outer wind maximum which can be what traditionally are called "hurricane force" wind warnings...there's storm warnings...50 knots...and then there are hurricane force storm warnings...65 knots...the entire NE seaboard can expect 50 to 65 knots not just one small area near the "eye" or "center" of the cyclone. Whether the center moves over your area is mute...your area will be impacted. There is no Central Dense Overcast; no eye, no inner eye core; this is an animal all to itself different and worse, it won't be going anywhere fast...there is an upper ridge over extreme eastern Canada...this cyclone's normal track is blocked, worse, this is a Negative Atlantic Oscillation upper high...very high heights aloft given the latitude of this upper high; it alters major weather patterns. We do not know if this is a 2012 version of the 1991 Perfect Storm or other hybrid weather events we've seen in past years.
I do not know what any of that means... LOL
Could you explain that in laymans terms for someone who doesn't know much about weather stuff?
I kind of understand, but not really...
| Random Chaos |
| (Weather Analyst) |
| Sun Oct 28 2012 09:38 AM |
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Re: Dodge MA and NH?
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12Z early track models have a southward shift to the southern Deleware Bay. This includes nearly total convergence from the AVNI, GFDI, and HWFI, plus variants and composites. This is the first time I've seen these models converge for landfall. Inland track is still slightly divergent, from following the PA/MD line to a northern Chesapeake Bay crossing. Several models are showing a brief retrograde before heading north.
| cieldumort |
| (Moderator) |
| Sun Oct 28 2012 11:28 AM |
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Re: Dodge MA and NH?
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In plain terms, there will be no "dodging" of anywhere in the northeast from Sandy. This is massive cyclone.
In simple terms, long-duration sustained brisk winds with locally damaging gusts are likely to be experienced just about everywhere east of the Mississippi for at least 2-3 days.
The Great Lakes will likely experience sustained very strong winds with gusts over hurricane force - possibly lasting over 30 hours, nonstop, creating incredible, possibly historic waves and surge.
The Appalachians will likely experience sustained very strong winds with some localized gusts above 100MPH (particularly mountain tops and in any terrain that creates a wind tunnel). This may last for at least 30 hours, nonstop.
East of the Apps, sustained very strong winds with some widespread gusts to at least 75 MPH are likely. This may also last for at least 30 hours, nonstop.
In addition to this phenomenal wind event, Sandy will generate moderate to locally heavy rains over basically the entire northeastern part of the country, with moderate to heavy snow over about the 2,000 elevation in the Apps.
Along the coast from about New Jersey to about Main, the potential exists for record-setting storm surge.
In a nutshell, Sandy is currently expected to set all kinds of records, and is a particularly dangerous system.
I am 100% confident her name will be retired.
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 01:33 PM |
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Re: Dodge MA and NH?
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Quote:
In plain terms, there will be no "dodging" of anywhere in the northeast from Sandy. This is massive cyclone.
In simple terms, long-duration sustained brisk winds with locally damaging gusts are likely to be experienced just about everywhere east of the Mississippi for at least 2-3 days.
The Great Lakes will likely experience sustained very strong winds with gusts over hurricane force - possibly lasting over 30 hours, nonstop, creating incredible, possibly historic waves and surge.
The Appalachians will likely experience sustained very strong winds with some localized gusts above 100MPH (particularly mountain tops and in any terrain that creates a wind tunnel). This may last for at least 30 hours, nonstop.
East of the Apps, sustained very strong winds with some widespread gusts to at least 75 MPH are likely. This may also last for at least 30 hours, nonstop.
In addition to this phenomenal wind event, Sandy will generate moderate to locally heavy rains over basically the entire northeastern part of the country, with moderate to heavy snow over about the 2,000 elevation in the Apps.
Along the coast from about New Jersey to about Main, the potential exists for record-setting storm surge.
In a nutshell, Sandy is currently expected to set all kinds of records, and is a particularly dangerous system.
I am 100% confident her name will be retired.
Thanks for explaining that.
As she moves farther north, NH is back in the cone.
I am not going to take any chances, and tomorrow will be going out to get things for the storm.
Weather here has been a "grey sky" and "light rain" on and off...
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danielw
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| (Moderator) |
| Sun Oct 28 2012 01:57 PM |
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Re: Dodge MA and NH?
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I would Not wait until tomorrow to stock supplies. Go now as stores further south in D.C. are already stripped bare of supplies.
As the others have stated above. No One knows what Sandy will do as far as damage goes.
Southern N.H NWS forecasts here:
http://www.erh.noaa.gov/box/index.php
Northern N.H. NWS Forecasts here:
http://www.erh.noaa.gov/gyx/
Click on the map for your Local Forecast and Warnings.
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 06:10 PM |
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Re: Dodge MA and NH?
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Quote:
I would Not wait until tomorrow to stock supplies. Go now as stores further south in D.C. are already stripped bare of supplies.
As the others have stated above. No One knows what Sandy will do as far as damage goes.
Southern N.H NWS forecasts here:
http://www.erh.noaa.gov/box/index.php
Northern N.H. NWS Forecasts here:
http://www.erh.noaa.gov/gyx/
Click on the map for your Local Forecast and Warnings.
All the schools are closing here...
I get this storm is very large, in size, but is it really going to be bad enough to have schools closed???
Mets are saying this:
Increasing northeasterly breezes take over tonight, but strong winds are not expected. A bit of drizzle and a passing shower is possible. Tomorrow: Northeasterly winds increase and become strong from midday into late Monday Night...Power outages are likely, especially in southeastern NH and in the higher terrain as gusts could hit 50+ mph. Rainfall...Even though the most torrential of the tropical rains are expected south and west of NH, a flood watch is in effect for late Monday PM into Tuesday. 1-3 inches of rain is expected which would not result in much flooding, but some spots(especially the higher terrain of southwestern NH and points north could get up to 4 or 5 inches of rain, which would result in some flooding. The heaviest rain looks to hit Monday pm into Tuesday AM with occasional showers on and off late Tuesday into Wednesday.
Been dreary here, kind of dark, winds are atleast 15-20mph with gusts... a nice breeze
| MichaelA |
| (Weather Analyst) |
| Sun Oct 28 2012 09:57 PM |
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Re: Dodge MA and NH?
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A 50 mph gust can blow a school bus off the road. The schools are closed because transporting children to and from school will be dangerous.
| Random Chaos |
| (Weather Analyst) |
| Sun Oct 28 2012 11:07 PM |
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Re: Dodge MA and NH?
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Last couple of IR frames look like an eyewall has formed.
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 11:33 PM |
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Re: Dodge MA and NH?
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Quote:
A 50 mph gust can blow a school bus off the road. The schools are closed because transporting children to and from school will be dangerous.
I wish they would tell that to the college...
all colleges closed here, except the one I attend...
Manchester community college is not closed... and we have students who come from all over....
Gonna be interesting... considering I ride public transportation...
| HobbyistinNH |
| (Verified CFHC User) |
| Sun Oct 28 2012 11:34 PM |
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Re: Dodge MA and NH?
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Quote:
Last couple of IR frames look like an eyewall has formed.
I saw that too. I thought that was not supposed to happen? I thought it was going to die down??
| Random Chaos |
| (Weather Analyst) |
| Sun Oct 28 2012 11:46 PM |
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Re: Dodge MA and NH?
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They did expect intensification just before it made the west turn, so this was somewhat expected, though I don't think anyone thought it would gain this kind of organization.
| cieldumort |
| (Moderator) |
| Mon Oct 29 2012 12:46 AM |
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Sandy: Subtropical Hurricane
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The reformation of an eyewall has actually been more or less foreseen by models, and in fact has been foreshadowed in earlier Discussions from the NHC.
The reason for this is primarily because shear is relaxing as the cyclone begins its recurvature back towards land, and at the same time the center is traveling over a locally warmer pocket of water.
While it is possible that Sandy retains distinctly tropical features up through landfall, extratropical transition has already begun, with the western portions of the cyclone merging with the stationary front that is draped basically N-S just inland. Moreover, water vapor images depict a cyclone that more resembles a mid-latitude neutral to cold core system than a tropical hurricane. And most telling, the regions of strongest winds have lied in belts well away from the center for some time now.
Sandy is basically a Subtropical Hurricane. In reality, these hybridized hurricanes have some history of being more damaging and deadly than their purely tropical counterparts of an identical Saffir-Simpson category. Keep in mind that the Saffir-Simpson is merely a 1-5 category of the maximum sustained winds regardless of how large an area they cover, or how frequently they are occurring.
| HobbyistinNH |
| (Verified CFHC User) |
| Mon Oct 29 2012 10:27 PM |
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Re: Sandy: Subtropical Hurricane
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I understand Sandy is still hurricane speed, moving at 85-90mph, but why is NHC classifying it as post-tropical? People are thinking that this is not a hurricane. Correct me if I'm wrong, but it is still a hurricane if over 75mph? Even if it is going through the transformation into a post tropical cyclone? I thought post tropical was lower than a depression? Kind of somewhat confused here...
(mods you can move this to where it needs to be if not appropriate, I am just confused...)
| ftlaudbob |
| (Storm Chaser) |
| Mon Oct 29 2012 10:46 PM |
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Re: Sandy: Subtropical Hurricane
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Quote:
I understand Sandy is still hurricane speed, moving at 85-90mph, but why is NHC classifying it as post-tropical? People are thinking that this is not a hurricane. Correct me if I'm wrong, but it is still a hurricane if over 75mph? Even if it is going through the transformation into a post tropical cyclone? I thought post tropical was lower than a depression? Kind of somewhat confused here...
(mods you can move this to where it needs to be if not appropriate, I am just confused...)
It went from a warm core system to a cold core system.That is the only real difference.