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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Quoting cchsweatherman:
I have a feeling that before this season is over, we'll see just exactly what the upper limits for hurricane strength are.
We may see something that resembles Wilma this year -- likely in the same location too (where the deepest OHC is located).
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Quoting StormW:


I think they may have the track a little far south prior to that, in some of those numbers I'm seeing. If I ever get another updated shear map to come up, and conditions are still forecast to be favorable, I wouldn't buy into that intensity scheme.
So, you are thinking stronger ?
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I'm still sticking with my thought of no Cat 5s this year.

(I know, what a horrible, horrible 'downcaster' I am...)
Member Since: August 23, 2008 Posts: 7 Comments: 5300
482. IKE
Quoting PSLFLCaneVet:
Wow, clipping along around 21 mph on average, if that verifies.


I was looking at the wrong number for the day of the month. It was in 6 days. I edited the post.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
481. IKE
Quoting MiamiHurricanes09:
I'm having a tough time understanding why most of the global models are no longer developing ex-Gaston into a tropical cyclone. Anyone know why?


Because they don't think it will develop.....



Member Since: June 9, 2005 Posts: 23 Comments: 37860
479. Vero1
Quoting StormW:


We could see development, which would be slow, but remember the size of Alex?

Yes
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Quoting IKE:


Interesting that that UKMET run carried Gaston to within 150-200 miles from the Yucatan in 4 days.
Wow, clipping along around 21 mph on average, if that verifies.
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I have a feeling that before this season is over, we'll see just exactly what the upper limits for hurricane strength are.
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Quoting btwntx08:
anticyclone near 90L


Thats not an anticyclone. Its just a pocket of lower shear.
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Quoting RecordSeason:
455:

That track is practically a worst case scenario, as it would eventually put Gaston right in the middle of the "off the scale" TCHP zone.

Very good point, that.
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Quoting Bordonaro:

Sorry, I was going by this map below from 7AM CDT today, posted a bit earlier today:


No problem. I just wondered if some could see the low placed on the NOAA floater and the loop with the movement a couple hours ago when it was easy to see. Right now I see it at about 19.9N and 95.7W on visible. It may be at 20.0N and is harder to see on a visible loop than an hour or so ago. Do you have a radar link from Mexico?
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I'm having a tough time understanding why most of the global models are no longer developing ex-Gaston into a tropical cyclone. Anyone know why?
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471. Vero1
Quoting StormW:


If upper level winds are conducive...think about Alex, and the other monsoonal developments we've had.


It would have to travel the length of the trof before "real" development begins?
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470. IKE
12Z ECMWF @ 144 hours...Link
Member Since: June 9, 2005 Posts: 23 Comments: 37860
anticyclone near 90L
Member Since: July 13, 2008 Posts: 6 Comments: 10796
Quoting Orcasystems:
Gaston is getting some legs...
The Florida Blob looks meaner...
That thing coming of Africa looks like it means it also..

I think I will go Golfing... brb



AOI

AOI

AOI

AOI

AOI

AOI


TS BUSTED FORECAST ALIBI

Look out for Fire Hydrants, and Irate spouses.
But have fun...
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467. IKE
Quoting stormwatcherCI:
Just curious about it because I had not seen this earlier.


I hadn't either.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
466. JLPR2
Well convection on the west side of Ex-Gaston and developing during the day too.
Looks like Gaston wants to recover its name soon.

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Quoting Orcasystems:
Gaston is getting some legs...
The Florida Blob looks meaner...
That thing coming of Africa looks like it means it also..

I think I will go Golfing... brb



AOI

AOI

AOI

AOI

AOI

AOI


TS BUSTED FORECAST ALIBI
I ain't never heard someone say, I'm going golfing brb....lol Afternoon Orcr and others.
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455:

That track is practically a worst case scenario, as it would eventually put Gaston right in the middle of the "off the scale" TCHP zone.
Member Since: June 13, 2010 Posts: 0 Comments: 2336
Quoting Cotillion:
AL, 90, 2010090518, , BEST, 0, 199N, 959W, 25, 1005, DB, 34, NEQ, 0, 0, 0, 0, 1008, 180, 60, 0, 0, L, 0, , 0, 0, INVEST, S,

Neither.


We do have a surface low, but convection is still rather disorganized and looks sheared.
Member Since: October 21, 2008 Posts: 246 Comments: 3970
Quoting IKE:


That track is where the 00Z ECMWF carried Gaston...toward Belize, Yucatan peninsula.
Just curious about it because I had not seen this earlier.
Member Since: Posts: Comments:
Gaston is getting some legs...
The Florida Blob looks meaner...
That thing coming of Africa looks like it means it also..

I think I will go Golfing... brb



AOI

AOI

AOI

AOI

AOI

AOI


TS BUSTED FORECAST ALIBI
Member Since: Posts: Comments:
440. AL, 09, 2010090518, , BEST, 0, 170N, 515W, 25, 1009, LO, 0, , 0, 0, 0, 0
did this come out for 90L yet
Member Since: July 13, 2008 Posts: 6 Comments: 10796
AL, 90, 2010090518, , BEST, 0, 199N, 959W, 25, 1005, DB, 34, NEQ, 0, 0, 0, 0, 1008, 180, 60, 0, 0, L, 0, , 0, 0, INVEST, S,

Neither.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
455. IKE
Quoting stormwatcherCI:


Have you seen this ? StormW, does this look about right? If so, it would be in the NW Caribbean. Cayman Islands is 19.2N and 81.2W

WTNT80 EGRR 051800


MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 05.09.2010

TROPICAL DEPRESSION GASTON ANALYSED POSITION : 16.8N 50.5W

ATCF IDENTIFIER : AL092010

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 05.09.2010 16.8N 50.5W WEAK
00UTC 06.09.2010 16.5N 52.6W WEAK LITTLE CHANGE
12UTC 06.09.2010 16.3N 55.6W WEAK LITTLE CHANGE
00UTC 07.09.2010 16.1N 59.3W WEAK LITTLE CHANGE
12UTC 07.09.2010 15.8N 62.3W WEAK INTENSIFYING SLIGHTLY
00UTC 08.09.2010 15.7N 65.2W WEAK LITTLE CHANGE
12UTC 08.09.2010 15.8N 68.6W MODERATE INTENSIFYING SLIGHTLY
00UTC 09.09.2010 15.8N 70.2W STRONG INTENSIFYING SLIGHTLY
12UTC 09.09.2010 16.5N 72.4W STRONG LITTLE CHANGE
00UTC 10.09.2010 17.2N 74.0W STRONG LITTLE CHANGE
12UTC 10.09.2010 17.2N 75.9W STRONG LITTLE CHANGE
00UTC 11.09.2010 17.5N 77.6W MODERATE WEAKENING SLIGHTLY
12UTC 11.09.2010 18.2N 80.0W MODERATE INTENSIFYING SLIGHTLY

TROPICAL STORM DEVELOPED IN THE MODEL ANALYSIS AT POSITION : 19.3N 95.1W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 05.09.2010 19.3N 95.1W MODERATE
00UTC 06.09.2010 20.8N 94.8W MODERATE WEAKENING SLIGHTLY
12UTC 06.09.2010 22.3N 96.1W MODERATE WEAKENING SLIGHTLY
00UTC 07.09.2010 24.1N 97.3W MODERATE LITTLE CHANGE
12UTC 07.09.2010 25.9N 98.6W WEAK LITTLE CHANGE
00UTC 08.09.2010 BELOW TROPICAL STORM STRENGTH




THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT

MET OFFICE, EXETER, UK


That track is where the 00Z ECMWF carried Gaston...toward Belize, Yucatan peninsula.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Gearsts:
We have Gaston?
No, those are the satellite estimates from SAB.
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Quoting MiamiHurricanes09:
05/1745 UTC 16.8N 51.1W T1.5/1.5 GASTON

05/1745 UTC 19.9N 95.5W T1.0/1.0 90L
We have Gaston?
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Quoting PSLFLCaneVet:
Send some of that dry air to Florida, please! We'll trade you some warm air this winter.


I wish I knew how to pull that off!!
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Have you seen this ? StormW, does this look about right? If so, it would be in the NW Caribbean. Cayman Islands is 19.2N and 81.2W

WTNT80 EGRR 051800


MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 05.09.2010

TROPICAL DEPRESSION GASTON ANALYSED POSITION : 16.8N 50.5W

ATCF IDENTIFIER : AL092010

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 05.09.2010 16.8N 50.5W WEAK
00UTC 06.09.2010 16.5N 52.6W WEAK LITTLE CHANGE
12UTC 06.09.2010 16.3N 55.6W WEAK LITTLE CHANGE
00UTC 07.09.2010 16.1N 59.3W WEAK LITTLE CHANGE
12UTC 07.09.2010 15.8N 62.3W WEAK INTENSIFYING SLIGHTLY
00UTC 08.09.2010 15.7N 65.2W WEAK LITTLE CHANGE
12UTC 08.09.2010 15.8N 68.6W MODERATE INTENSIFYING SLIGHTLY
00UTC 09.09.2010 15.8N 70.2W STRONG INTENSIFYING SLIGHTLY
12UTC 09.09.2010 16.5N 72.4W STRONG LITTLE CHANGE
00UTC 10.09.2010 17.2N 74.0W STRONG LITTLE CHANGE
12UTC 10.09.2010 17.2N 75.9W STRONG LITTLE CHANGE
00UTC 11.09.2010 17.5N 77.6W MODERATE WEAKENING SLIGHTLY
12UTC 11.09.2010 18.2N 80.0W MODERATE INTENSIFYING SLIGHTLY

TROPICAL STORM DEVELOPED IN THE MODEL ANALYSIS AT POSITION : 19.3N 95.1W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 05.09.2010 19.3N 95.1W MODERATE
00UTC 06.09.2010 20.8N 94.8W MODERATE WEAKENING SLIGHTLY
12UTC 06.09.2010 22.3N 96.1W MODERATE WEAKENING SLIGHTLY
00UTC 07.09.2010 24.1N 97.3W MODERATE LITTLE CHANGE
12UTC 07.09.2010 25.9N 98.6W WEAK LITTLE CHANGE
00UTC 08.09.2010 BELOW TROPICAL STORM STRENGTH




THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT

MET OFFICE, EXETER, UK
Member Since: Posts: Comments:
449. Vero1
StormW~~With what is coming off Africa is south of the Monsoonal Trof, what can be expected for development?

...ITCZ...

A MONSOONAL TROUGH EXTENDS FROM THE COASTAL WATERS OF W AFRICA
NEAR 19N20W ALONG 10N23W TO 6N35W...WHERE THE ITCZ AXIS BEGINS
AND CONTINUES WESTWARD ALONG 10N45W TO 12N60W. SCATTERED
MODERATE TO STRONG CONVECTION IS E OF THE TROUGH FROM 6N TO 14N
BETWEEN THE COAST OF WEST AFRICA AND 22W. CLUSTERS OF SIMILAR
CONVECTION ARE FROM 4N TO 8N BETWEEN 30W-43W.

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SAB: T1.5.
TAFB: T2.0.

The NHC could upgrade ex-Gaston to a tropical depression based on the T-numbers. They may want to wait until tonight to see if the convection wanes or not though.

TAFB, GR, VI, 3, 2020 /////, , , GOES13, CSC, T, DT = 2.0 BASED ON 0.3 BANDING. NLINEMET= 2.5 PAT=
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Be back later...
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TAFB: Gaston 2.0/2.0
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Vero1:


Pottery, since nothing is going on could you start putting ice cubes in the Carib?

Waddaya mean??
It's Party time here.
ALL ice cubes are reserved....
Sorry, man.

Have you tried tunnels?
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Quoting PrivateIdaho:
Gusting to near TS strenght here...check out the dewpoint...thought some of you would get a kick out of that. Of course our fire danger is extreme today. :^(

Pocatello, Pocatello Regional Airport
Last Update on 05 Sep 11:53 MDT


Partly Cloudy

65°F
(18°C) Humidity: 23 %
Wind Speed: WSW 24 G 36 MPH

Barometer: 29.94 in (1009.80 mb)
Dewpoint: 26°F (-3°C)
Visibility: 10.00 Miles
More Local Wx: 3 Day History:



Send some of that dry air to Florida, please! We'll trade you some warm air this winter.
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Station 41040
NDBC
Location: 14.477N 53.008W
Conditions as of:
Sun, 05 Sep 2010 17:50:00 UTC
Winds: WSW (240°) at 1.9 kt gusting to 3.9 kt
Significant Wave Height: 4.3 ft
Dominant Wave Period: 9 sec
Atmospheric Pressure: 29.89 in and falling
Air Temperature: 84.6 F
Water Temperature: 85.6 F
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441. IKE
Five day(120 hours), ECMWF....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
AL, 09, 2010090518, , BEST, 0, 170N, 515W, 25, 1009, LO, 0, , 0, 0, 0, 0
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Quoting StormW:


Pottery,
you bringin the beer?

Sounds like a Plan, to me.
er, um, what's the Superbowl?
Like a Punchbowl, but with Additives??

(heheheh)
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438. Vero1
Quoting StormW:




Pottery, since nothing is going on could you start putting ice cubes in the Carib?
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Quoting StormW:




Thanks Storm, you're quicker at this blogging stuff!
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Thanks...
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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