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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1385. Grothar
First time we have seen yellow close to the center. That is some very cold cloud tops beginning to form.

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Ok. It's renumber time. No renumber in the next 10 minutes...no TD or TS.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StormW:
RitaEvac,
Right now, if 90L doesn't come up with any eastward or NE motion, I don't see it being around too long. Based on what the position appears to be, I don't see it coming in at TX right now.


Good, thanks.
Member Since: July 14, 2008 Posts: 1 Comments: 9630
Quoting Tazmanian:



plzs dont Quote him i had too Ignore him he has started posting that too a point too where it be come vary annyoing
LOL, he's not a troll...he posts excellent information actually.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1381. BDADUDE
Quoting kmanislander:


Getting close to the "sweet spot" at 55 W

If Gaston blows up then caymanians will have nothing to worry about from this storm because it will turn NW.
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this was a double post, sorry don't know how it happened.
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huy the NHC lowered Gaston to 60% but it is starting to fire some convection over the center. I say TD tomorrow.
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1376. HadesGodWyvern (Mod)
haven't had any problems with loading either..
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Quoting JLPR2:


Maybe, just maybe, this d-max might be different for Gaston, seems he has more moisture to work with than before.


Getting close to the "sweet spot" at 55 W
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting CaicosRetiredSailor:
Kman

Yes Lots of problems refreshing Wunderground pages here also!


me too... idk whats going on its been the last 2 days
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WU works find for me
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Quoting KoritheMan:
I just did a blog entry on 90L, Gaston, and the wave the models forecast to develop. Enjoy!
Thanks Kori. Good analysis.
Member Since: October 9, 2008 Posts: 0 Comments: 8391
Quoting CaicosRetiredSailor:
Kman

Yes Lots of problems refreshing Wunderground pages here also!


Slow as molasses in winter flowing uphill.
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BROWNSVILLE/SOUTH PADRE IS, TX, United States

Conditions at Sep 05, 2010 - 08:53 PM EDTSep 05, 2010 - 07:53 PM CDTSep 05, 2010 - 06:53 PM MDTSep 05, 2010 - 05:53 PM PDTSep 05, 2010 - 04:53 PM ADTSep 05, 2010 - 03:53 PM HDT
2010.09.06 0053 UTC
Wind from the ENE (070 degrees) at 5 MPH (4 KT)
Visibility 8 mile(s)
Sky conditions overcast
Weather Light rain
Precipitation last hour A trace
Temperature 79.0 F (26.1 C)
Dew Point 75.0 F (23.9 C)
Relative Humidity 87%
Pressure (altimeter) 29.78 in. Hg (1008 hPa)
ob KBRO 060053Z 07004KT 8SM -RA FEW027 SCT055 OVC075 26/24 A2978 RMK AO2 RAB39 SLP084 P0000 T02610239
Member Since: August 23, 2008 Posts: 0 Comments: 1918
Quoting CaicosRetiredSailor:
Kman

Yes Lots of problems refreshing Wunderground pages here also!


me too... idk whats going on its been the last 2 days
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1368. JLPR2
Quoting kmanislander:


Thanks. Bookmarked. That is the 25 KM imagery.

Gaston now firing deep convection right over the center. This is the first time in days this has happened.



Maybe, just maybe, this d-max might be different for Gaston, seems he has more moisture to work with than before.
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Quoting StormW:


Thanks!



plzs dont Quote him i had too Ignore him he has started posting that too a point too where it be come vary annyoing
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Quoting StormW:


Na...neither one of them has the interest.


Well if you ever want to adopt a 31 year old i want to learn. :)
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Kman

Yes Lots of problems refreshing Wunderground pages here also!
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1360. Vero1
Quoting StormW:
Anyone have a "good" center fix for 90L? Looks to me, it's west of the convection.


TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 05 2010

A 1005 MB LOW OFF VERACRUZ MEXICO IS NEAR 20N96W. A TROUGH
EXTENDS N FROM THE LOW TO 26N95W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 19N-26N BETWEEN 93W-99W. SHORT RANGE
COMPUTER MODELS SUGGEST THIS SYSTEM WILL CONTINUE TO MOVE NNW
OVER THE NEXT COUPLE OF DAYS. ENVIRONMENTAL CONDITIONS APPEAR
FAVORABLE FOR ADDITIONAL DEVELOPMENT AND A TROPICAL DEPRESSION
COULD FORM DURING THE NEXT DAY OR SO BEFORE THE SYSTEM MOVES
INLAND. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS

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Quoting JLPR2:


That page updates faster than the one you posted, dont ask me why. XD


Thanks. Bookmarked. That is the 25 KM imagery.

Gaston now firing deep convection right over the center. This is the first time in days this has happened.

Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting StormW:


I actually have 2 teenagers.


Hope they arent anything like me when i was one! I do have to ask though, do they know their weather?
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Heading for land??? OookkK.....You could clearly see earlier looking at the vis. sat. 90l had a north-nnw movement...
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Major NEward zag from 90L's previous NNWward zig.
Copy and paste 18.4n95.8w, 18.6n95.7w, 18.9n95.7w, 19.1n95.7w-19.2n95.6w, 19.2n95.6w-19.4n95.6w, 19.4n95.6w-19.9n95.9w, 19.9n95.9w-20.4n95.4w, mid, bro into the GreatCircleMapper for a look at the last 24hours.

90L had turned its heading to 1.7degrees north of NorthEast,
and had increased its moving speed up to ~7.8mph(~12.6km/h);
more than doubling its distance from the nearest coastline.
The NHC has upped the probability of 90L becoming a TropicalDepression to 80%.
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DestinJeff has fallen and cannot get up, - but he did text me his Gas-Tone predictions.


He says "Gas-Tone may or may not regenerate into a hurricane, if it does it could or could not become a major. If it becomes a major, Kman will accept paypal contirbutions for new tightie whities.


Gas-tone could also just wilt away, or maybe not.


The one certain is that the CHART will be posted again tomorrow - or maybe not.


Evening all, long time lurker, just started posting lately. Orca, love your blogs humor, it's all about finding the humor, along with good info.

Back to lurking.

Evening StromW.
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1350. HadesGodWyvern (Mod)
Quoting Ameister12:
Korea round 3.





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Gaston and 90L sould be bump up too 100% next two
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TAFB also came in at T1.5 for 90L. Based on that they could make this a 30mph TD, but these estimates are a secondary resource. Keep in mind that 90L is located in the GOM, a lot of buoys, stations, radar, etc... are easily accessible to determining a more suitable and accurate intensity and based on the 1003mb pressure, it may be higher than 30mph.

TAFB
, WB, VI, 5, 1515 /////, , , GOES13, CSC, T, DT = 1.5 BASED ON 0.3 BANDING. NLINEMET= 0.0 PAT=
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1345. Vero1
Quoting RitaEvac:
What the hell, Houston, Corpus, and Brownsville radar sites are still down for maint.... they getting ready for a storm or what.


NEXRAD appears down BUT NWS Radar is up!! Brownsville:

http://radar.weather.gov/Legend/N0R/BRO_N0R_Legend_0.gif
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1344. JLPR2
Gaston seems to be doing better, ready to fire up another area of convection.
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Member Since: August 23, 2008 Posts: 0 Comments: 1918
Storm,

You must have a teenager(or preparing for one like me) cause you always pop up when things are fixing to get good lol!
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Quoting kmanislander:


I don't think that is from this evening. Ascat has not downloaded that far West for tonight.


the coordinates look right
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Have people saying NNE movement and I dont see it.
Member Since: July 14, 2008 Posts: 1 Comments: 9630
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Lots of deep convection beginning firing around the circulation when it should be waning.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
1335. JLPR2
Quoting kmanislander:


No data for that area downloaded here


That page updates faster than the one you posted, dont ask me why. XD
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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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