Gaston still a threat to redevelop

By: Dr. Jeff Masters , 3:17 PM GMT on September 05, 2010

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For the first time since August 22, when Danielle became a tropical storm, there are no named storms active in the Atlantic. An extratropical storm absorbed Tropical Storm Earl last night, bringing an end to the 11-day life of the 2010 season's longest-lived storm. While Earl was mostly a non-event for North Carolina and New England, the storm gave Nova Scotia a solid pounding, reminding us of what could have easily happened to New England had the forecast track deviated slightly to the left. Kudos go to the computer models and NHC, who successfully predicted the path of Earl very accurately four days in advance. As we approach the climatological peak of Atlantic hurricane season, which occurs on September 10, there are no indications that today's break in the action represents a beginning of an extended quiet period in the Atlantic. Indeed, we have two systems that could become tropical depressions in the next day, and we also have model predictions of another storm to come late in the week.


Figure 1. Morning satellite image of the remains of Gaston, approaching the Lesser Antilles Islands.

Gaston near tropical depression status again
The remains of Tropical Storm Gaston, located about 700 miles east of the Lesser Antilles Islands and moving west at about 13 mph, are close to reaching tropical depression status again. Recent satellite imagery shows that Gaston's remains have developed a well-organized surface circulation, but not enough heavy thunderstorm activity to be considered a tropical depression. A large amount of dry air surrounds Gaston's remains on all sides, as seen on water vapor satellite loops. This dry air will continue to be a major impediment to development. The latest SHIPS model forecast predicts shear will remain moderate, 10 - 15 knots, for the next three days, then fall to the low range. The winds creating the shear are coming from the east, where a tongue of dry air has intruded. These easterly winds will be able to drive the dry air into Gaston's core, disrupting it, unless the storm can find a moister environment, or moisten its environment on its own by generating enough heavy thunderstorms. Gaston has managed to develop more heavy thunderstorms near its center of circulation late this morning, but the amount of dry air it is battling is formidable. Even if Gaston does manage to become a tropical depression today, development will be slow over the next few days, due to the dry air. When Gaston passes over or just to the northeast of the Lesser Antilles Islands early Tuesday morning, the storm is unlikely to have more than 50 mph winds. More significant development is possible later in the week, as the atmosphere should be moister for Gaston. Gaston may threaten Puerto Rico on Wednesday, the Dominican Republic on Thursday, and Haiti, Jamaica, and/or the Turks and Caicos Islands by Friday, depending upon the storm's interaction with a trough of low pressure expected to move off the U.S. East Coast later this week. The earlier Gaston develops into a tropical storm, the more likely it is to "feel" the upper-level winds of the approaching trough, and curve more to the northwest. The HWRF model predicts Gaston will develop by Monday, and pass just northeast of the Lesser Antilles Islands Tuesday morning. The GFDL model, on the other hand, delays development until Wednesday, keeping Gaston in the Caribbean. The GFDL has Gaston hitting Jamaica as a strong tropical storm on Friday morning. However, the GFDL forecast is dubious, because on Wednesday and Thursday, Gaston may have an encounter with the high mountains of the island shared by the Dominican Republic and Haiti, Hispaniola, which could easily destroy a system as fragile as Gaston. Gaston has a 70% chance of developing into a tropical depression by Tuesday, according to NHC.

Gulf of Mexico disturbance 90L
A concentrated area of heavy thunderstorms (90L) has developed over the extreme southwestern Gulf of Mexico, in the Bay of Campeche. Satellite imagery shows that this disturbance is disorganized, but has some modest spin to it. The disturbance is under a moderate 10 - 15 knots of wind shear, and has a 60% chance of developing into a tropical depression by Tuesday, according to NHC. The disturbance is headed northwest at 5 - 10 mph, and should bring heavy rains to the Texas/Mexico border region on Monday, according to the latest run of the GFS model. The main impediment to development will be the limited time 90L has over water; the storm will be ashore by Tuesday, which doesn't give it much time to develop.

Elsewhere in the tropics
The GFS and NOGAPS models are predicting development on Thursday of a tropical wave that will emerge from the coast of Africa on Tuesday or Wednesday.

Next post
I'll have an update Monday morning.

Jeff Masters

Sunrise Surf was cranking (RIWXPhoto)
Sunrise Surf was cranking
Post Hurricane Earl surf photos at Newport, RI (RIWXPhoto)
Post Hurricane Earl surf photos at Newport, RI

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Good morning from upstate New York. Hermine looks impressive right now, and seems to have a little more time over water than was thought yesterday. With her current rate of organization and strengthening, a category 1 storm is not out of the question. Hopefully everyone is the warning area is taking precautions.
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2334. IKE
Quoting jurakantaino:
Yes. and embarrassing the NHC,all the time they hype the storm: "an advices will begin to the islands at any time today", since Friday they been saying that.... "poof"...


I will admit their forecasts for Gaston haven't been the best.
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Quoting weatherman12345:

Moved out of dry air already but is in a pocket of shear right now


WV sat - Pulling in dry air from east and band of dry air to his west? LOL, that looks to be a "large pocket" of shear. Just wondering if these 3 issues are why the models are hesitant to develop Gaston for now.

Thanks for the reply.
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Quoting ozzyman236:
because gaston is already R.I.P.


So Gaston is going off the rails of a "Crazy Train?"
Member Since: July 7, 2005 Posts: 0 Comments: 5417
Quoting RecordSeason:
Gaston is starting his same old boring cycle again, rebuilding the SW quadrant convection that will then try to wrap into the CoC, only to be sheared off again....
Yes. and embarrassing the NHC,all the time they hype the storm: "an advices will begin to the islands at any time today", since Friday they been saying that.... "poof"...
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Ozzy, Hermine is not occupying their time?
Member Since: October 21, 2008 Posts: 248 Comments: 3970
Quoting TXCaneCrasher:


No, not yet. Have you? If so, what are you seeing?


This was posted this morning
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I agree Relix, Gaston is headed for the western Caribbean Sea where things can get going. For now our biggest concern is Hermine.
Member Since: October 21, 2008 Posts: 248 Comments: 3970
2324. tkeith
Quoting ozzyman236:
the NHC is just looking for something to occupy there time..they know gaston is R.I.P.
we have another NHC insider...can't have enough of those.
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2323. IKE
Almost looks like Gaston's convection has turned into a surge of moisture caught in a building high pressure system....racing west. The ULL to it's west doesn't seem to be a problem yet. It's moving in tandem with Gaston.

Hermine looks like a big rain maker and a strong TS at landfall...maybe a low end cat 1.
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2322. Vero1
Quoting Chicklit:
#2294: I think that's Igor.


...TROPICAL WAVES...

TROPICAL WAVE REMAINS INLAND OVER W AFRICA ALONG 14W MOVING W NEAR 10 KT. A WEAK 1012 MB LOW IS ALONG THE WAVE AXIS NEAR 10N.


I think Igor is the 1010 Low

Member Since: July 21, 2008 Posts: 4 Comments: 2233
Man the wave emerging off of Africa is a beast.
Member Since: October 21, 2008 Posts: 248 Comments: 3970
2320. scott39
Quoting ozzyman236:
the NHC is just looking for something to occupy there time..they know gaston is R.I.P.
Really? Really? oh Really????LOL
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2319. Relix
Gaston should become something more down the road, just not where it is now
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Quoting HadesGodWyvern:


maybe, Chicklit


Impressive structure, maybe that's the GFS's wave that it spins up?
Member Since: July 8, 2005 Posts: 259 Comments: 24576
Good Morning......Sorry about double post.
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Good Morning and Happy Labor Day. Some very heavy rain bands headed towards Brownsville this morning from Hermine.
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2312. ackee
what will become of EX Gaston

A TD
B TS
c TROPICAL LOW
D DISSPIATE
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Oh no, I am going to bust too low with the intensity of 90L/10LHermine. This happened real fast. It repositioned to the northeast which I and StormW said that would need to occur in order for this system to intensify more rapidly. Right now this is one of the best looking tropical cyclones of the season in terms of structure. CDO, two outflow channels and spiral banding present. Earl, and Danielle had one real outflow channel (poleward) while ALex was probably the best looking storm of the season, but ran out of time before any real rapid intensification could have occurred and the same will go for Hermine. I think she could peak at 75mph hurricane before landfall.
Member Since: October 21, 2008 Posts: 248 Comments: 3970
Quoting blsealevel:


Yes it would "imo" it is moving NNE or even more NE at this time so storm would have to make a left turn at the red light sort of speak
have you looked at the stearing pattern yet for the GOMEX?



No, not yet. Have you? If so, what are you seeing?
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2307. scott39
Quoting ozzyman236:
because gaston is already R.I.P.
Tell the NHC that. Whats even more confusing is that the GFS has it in a good enviroment in the near future with no developement.
Member Since: June 13, 2009 Posts: 0 Comments: 6912
Looking at shear map, isn't Gaston getting ready to enter an area of 20-30 kt shear to his west(from a nearby TUTT)?

If so, he has 3 things fighting him. Dry air, shear and the future potential for land interaction?

All of this is a question, not a statement of fact. In other words, please correct as necessary.

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2304. HadesGodWyvern (Mod)


maybe, Chicklit
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2302. Hhunter
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#2294: I think that's Igor.


...TROPICAL WAVES...

TROPICAL WAVE REMAINS INLAND OVER W AFRICA ALONG 14W MOVING W NEAR 10 KT. A WEAK 1012 MB LOW IS ALONG THE WAVE AXIS NEAR 10N.
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2299. scott39
Why are the global models not picking up on ex-Gaston developing?
Member Since: June 13, 2009 Posts: 0 Comments: 6912
Good morning all. I see this is now TS Hermine.
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2297. HadesGodWyvern (Mod)
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Quoting blsealevel:


Yes it would "imo" it is moving NNE or even more NE at this time so storm would have to make a left turn at the red light sort of speak
have you looked at the stearing pattern yet for the GOMEX?



What spot NNE or NE of 22.4/95.3 do you think the center is?
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Hermine'10 comparible to Jose'05-it can be a hurricane,but it's unlikely(now)...
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2294. Vero1
Ok:

Bermuda?
East Coast?
FL?
GOM?

Member Since: July 21, 2008 Posts: 4 Comments: 2233
2293. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #31
SEVERE TROPICAL STORM MALOU (T1009)
21:00 PM JST September 6 2010
================================

SUBJECT: Category Two Typhoon In East China Sea

at 12:00 PM UTC, Severe Tropical Storm Malou (985 hPa) located at 32.7N 127.2E has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving east northeast at 7 knots

Dvorak Intensity: T3.0

Gale Force Winds
=================
210 NM from the center in southeastern quadrant
130 NM from the center in northwestern quadrant

Forecast and Intensity
========================
24 HRS: 34.9N 129.4E - 55 knots (CAT 2/Severe Tropical Storm)
48 HRS: 36.9N 135.6E - 50 knots (CAT 2/Severe Tropical Storm)
72 HRS: 37.0N 143.7E - 35 knots (CAT 1/Tropical Storm)
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Quoting dan77539:
On Hermine, is that a re-positioning of the center at 23N/96W? That was the NHC's 1800Z position forecast. If so, it will spend less time over water. That probably doesn't change the flood potential much, though, and that's the big impact we'd expect from Hermine.


Oh, my mistake. This jump is the one they already discussed in the 0900Z forecast.
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2291. IKE
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Tides here in Corpus Christi are already 2ft above MSL as recorded at Bob Hall Pier on North Padre Island. I'm REAL currious what the winds are going to be come 10 a.m. advisory (CDT) to find out if we are dealing with a truly rapidly intensifying system or not.
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2288. Walnut
TS Hermine looking good this morning. Guess we are going to get a little damp here in San Antonio. It really looks like it is getting organized quickly. Any chance she gets to Cat 1 before landfall? The area of what we call Deep South Texas has had plenty of rain and the Rio Grande "pools" are pretty high. Prayers to those in the valley for possible flooding. To those in the Texas Hill Country - don't forget: Turn Around, Don't Drown.
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2287. 7544
wouldnt the trof push h to the neast soon or is it too far from the trof tia
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Quoting TXCaneCrasher:


My issue with this picture is I don't see Hermine making that much of a Westward move for her next position. IMO. I see her a little further North of that so wouldn't that move the cone a little more into Texas?


Yes it would "imo" it is moving NNE or even more NE at this time so storm would have to make a left turn at the red light sort of speak
have you looked at the stearing pattern yet for the GOMEX?

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2285. tkeith
Quoting kmanislander:


More often than good LOL
lol...like me ya got your moneys worth :)
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