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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Large and hopefully informative update on Hermine and Gaston.

Tropical Storm Hermine and the remnants of Gaston 9/6/10
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Quoting Relix:


Earl at least had a stronger circulation and worthy convection. Also he started exploding past 50W. Gaston is nearing 55W and still exposed once more, same story from last 2 days. I have a very bleak outlook for it at the moment XD!


Bleak for whom?

It is dangerous to write off such systems

You'll be better off being here until it hits and then going to the supermarket for the price markups :)
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2232. tkeith
Quoting IKE:
Hermine is strengthening...you can see the banding better on satellite.
probably gonna be some big 'ol Texas BBQ's rained on today...
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wow i wake up and there's a potential CAT1 heading towards south texas coast... wow

it appears this North/NNW motion could continue for a while looking at satellite/water vapor...

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2230. aquak9
(sneaks in, nods head at folks, sits at far end of counter)
Member Since: August 13, 2005 Posts: 163 Comments: 25732
Quoting tropicfreak:


It will move out of the area of dry air. Get the facts straight.

It could be too late to survive land interaction. LOL
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Quoting tropicfreak:


The dry air keeps following him. Would they stop picking on him?? LOL


Personally, I hope his lungs explode with the stuff.
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If everyone thinks Gaston is dead, then why all the talk on it? It is just the same posts over and over lol. What about Hermine? At least she is a threat in the next 24-36 hours here in Texas.
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2226. Hhunter
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2225. 7544
morning enjoy ur coffee everyone

well we got the letter h now so bring on IGOR

gaston trying looks to be heading further wnw today

when could we see 91L ?
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Quoting IKE:
Hermine is strengthening...you can see the banding better on satellite.


the NHC will have to shift the cone further north, and at this rate of intensification, we could be talking about a cat1 hurricane making landfall on TX. Kind of reminds me of alex earlier this season after he strengthened right as he reemerged off the yucatan and quickly became a cat 2 hurricane.
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Quoting aspectre:
TropicalStormHermine's heading had turned westward to (3.3degrees north of) NorthNorthWest
from its previous heading of dueNorth
TD.10's average speed moving between its last 2 reported positions was ~19.3mph(~31.1km/h)

05Sep . 12pmGMT - - 19.5n95.7w - - 25knots - - 1005mb - - NHC-ATCF *19.4n95.6w
05Sep . 06pmGMT - - 19.9n95.7w - - 25knots - - 1004mb - - NHC-ATCF *95.9w
06Sep . 12amGMT - - 20.4n9.54w - - 25knots - - 1003mb - - NHC-ATCF
TD.10 -- 3hour intervals between positions (including the previous one and the next)
06Sep . 03amGMT - - 20.7n95.2w - - 30mph - - 1003mb - - NHC.Adv.#1
06Sep . 06amGMT - - 20.9n95.0w - - 35mph - - 1003mb - - #1A
TD.10 becomes TS.Hermine
06Sep . 09amGMT - - 21.6n95.0w - - 40mph - - 1001mb - - #2
06Sep . 12pmGMT - - 22.4n95.3w - - 45mph - - - 995mb - - #2A

25knots=~28.8mph __ ~26.1knots=30mph

Copy and paste 19.5n95.7w, 19.9n95.7w, 20.4n95.4w-20.7n95.2w, 20.7n95.2w-20.9n95.0w, 20.9n95.0w-21.6n95.0w, 21.6n95.0w-22.4n95.3w, mid, bro into the GreatCircleMapper for a look at the last 12^hours.

* Before the NHC reevaluated&alterered the ATCF numbers.
^ The dots preceeding the four line-segments show positions that were measured 6hours apart.


That Figures
Member Since: August 23, 2008 Posts: 0 Comments: 1918
2221. Gearsts
Quoting kmanislander:


The map I posted shows that clearly does it not ?. I was making the point that Gaston is currently sitting in a pocket of strong shear.
Gaston is rapidly closing in on 60 W and once it reaches 63 the odds of regeneration fall historically until 75 W
Member Since: August 2, 2010 Posts: 0 Comments: 1430
Everyone is defying what ex-Gaston could do.

I think, if the NHC has kept high hopes on this system so far, something is bound to happen.

With all these systems, we see convection drop, re-form and visa-versa and I don't think we can let go of ex-Gaston just yet.

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good grief!
Member Since: July 11, 2006 Posts: 14 Comments: 11174
2218. Hhunter
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2217. IKE
Hermine is strengthening...you can see the banding better on satellite.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Chavalito:
Definitively, Gaston is dead. I've heard a lot of people indicating that when it got to 55W, he would overcome everything. But, as all of us have been seen, dry air has killed Gaston. Gaston is over.


Don't go out on a limb like this much, but I disagree with this post. Time will tell...for now I still think it bears watching.
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Wow i think there could be a crow shortage soon!

Guys in the gulf watch hermione with wary eyes - wait... not the harry potter chick
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Mornin,
Seventy percent is a high probability for the NHC.
Loop
Member Since: July 11, 2006 Posts: 14 Comments: 11174
Imo gaston looks structurally more organized today than yesterday, i give him a whoppin 80-90% of becoming a td before midnight....
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2212. IKE


Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Gearsts:
You do know that the shear is moving away faster to the wnw?


The map I posted shows that clearly does it not ?. I was making the point that Gaston is currently sitting in a pocket of strong shear.
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2210. Gearsts
Quoting Chavalito:
Definitively, Gaston is dead. I've heard a lot of people indicating that when it got to 55W, he would overcome everything. But, as all of us have been seen, dry air has killed Gaston. Gaston is over.
I see him alive!Not well but alive.
Member Since: August 2, 2010 Posts: 0 Comments: 1430
2209. Relix
Quoting serialteg:


Remember earl... rapid intensification did not start until right next to the carib


Earl at least had a stronger circulation and worthy convection. Also he started exploding past 50W. Gaston is nearing 55W and still exposed once more, same story from last 2 days. I have a very bleak outlook for it at the moment XD!
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Is it me or Hermine is huge? This really grew from last night, or let me say SHE. :)
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Quick intensification is beginning to take place it appears on Hermine.

AL, 10, 2010090612, , BEST, 0, 226N, 954W, 45, 998, TS,

Now up to 50 mph.
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TropicalStormHermine's heading had turned westward to (3.3degrees north of) NorthNorthWest
from its previous heading of dueNorth
TD.10's average speed moving between its last 2 reported positions was ~19.3mph(~31.1km/h)

05Sep . 12pmGMT - - 19.5n95.7w - - 25knots - - 1005mb - - NHC-ATCF *19.4n95.6w
05Sep . 06pmGMT - - 19.9n95.7w - - 25knots - - 1004mb - - NHC-ATCF *95.9w
06Sep . 12amGMT - - 20.4n9.54w - - 25knots - - 1003mb - - NHC-ATCF
TD.10 -- 3hour intervals between positions (including the previous one and the next)
06Sep . 03amGMT - - 20.7n95.2w - - 30mph - - 1003mb - - NHC.Adv.#1
06Sep . 06amGMT - - 20.9n95.0w - - 35mph - - 1003mb - - #1A
TD.10 becomes TS.Hermine
06Sep . 09amGMT - - 21.6n95.0w - - 40mph - - 1001mb - - #2
06Sep . 12pmGMT - - 22.4n95.3w - - 45mph - - - 995mb - - #2A

25knots=~28.8mph __ ~26.1knots=30mph

Copy and paste 19.5n95.7w, 19.9n95.7w, 20.4n95.4w-20.7n95.2w, 20.7n95.2w-20.9n95.0w, 20.9n95.0w-21.6n95.0w, 21.6n95.0w-22.4n95.3w, mid, bro into the GreatCircleMapper for a look at the last 12^hours.

* Before the NHC reevaluated&alterered the ATCF numbers.
^ The dots preceeding the four line-segments show positions that were measured 6hours apart.
Member Since: Posts: Comments:
Quoting Chavalito:
Definitively, Gaston is dead. I've heard a lot of people indicating that when it got to 55W, he would overcome everything. But, as all of us have been seen, dry air has killed Gaston. Gaston is over.


It will move out of the area of dry air. Get the facts straight.
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Quoting Relix:


He will be nothing. Even if he does pull off something this close it won't be anything big. Expect a usual rainy day with some gusts. That's all.


Remember earl... rapid intensification did not start until right next to the carib
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2203. Gearsts
Quoting kmanislander:
Good morning

Gaston still maintains a respectable circulation with a strong 850 mb vort. Dry air has been forced once again into the center of the low by 25 knot Easterly winds which have plagued the system off and on for days. It sits right in a small pocket of strong shear at the moment and this is evident from the way in which the clouds are oriented and stretched out from the SE to the NW.

Gaston is rapidly closing in on 60 W and once it reaches 63 the odds of regeneration fall historically until 75 W. The only thing going for Gaston that might help him overcome the " John Hope rule " is that the circulation was closed for the past several days and all it lacked was convection. It is difficult to tell whether it is still closed but if not it wouldn't take much to close up again if convection can really fire.

I wouldn't write this one off yet.

The image below shows the pocket of shear I have just mentioned.

You do know that the shear is moving away faster to the wnw?
Member Since: August 2, 2010 Posts: 0 Comments: 1430
2202. Relix
I'll say it again. At least for us in the islands we are just dealing with a rain event, maybe some gusts. The THCP is there, the dry air is still around and the shear is killing whatever it tries to come up with. He's a fighter for sure, but he won't regenerate around the islands.
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Definitively, Gaston is dead. I've heard a lot of people indicating that when it got to 55W, he would overcome everything. But, as all of us have been seen, dry air has killed Gaston. Gaston is over.
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Quoting IKE:
Looks headed just north of the northern islands.....moving just north of west?



Not sure I could call that even a tad north of west. Looks due west to me... Morning Ike
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Quoting HouGalv08:
Quoting Bastardi day before yesterday, he said that if Gaston stayed together and made it to 50W, thats where the storm would come alive. Well, the C.O.C is just passing 50W now. Lets see what happens.
And StormW, ya can't possibly be serious saying the C.V. season is over. I think you meant that as a joke?


He was using sarcasm.
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2198. tkeith
Alex
Bonnie
Colin
Danielle
Earl
Fiona
Gaston
Hermine
Igor

Julia
Karl
Lisa
Matthew
Nicole
Otto
Paula
Richard
Shary
Tomas
Virginie
Walter

well on the bright side, we're getting to the point of having a little more conventional names for Storms...
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2197. Vero1
Quoting StormW:


Season's over.


TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON SEP 06 2010

...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.
Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting IKE:
Looks headed just north of the northern islands.....moving just north of west?



If it mov e N of the Islands, is a real RIP?
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Quoting Bastardi day before yesterday, he said that if Gaston stayed together and made it to 50W, thats where the storm would come alive. Well, the C.O.C is just passing 50W now. Lets see what happens.
And StormW, ya can't possibly be serious saying the C.V. season is over. I think you meant that as a joke?
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Good morning

Gaston still maintains a respectable circulation with a strong 850 mb vort. Dry air has been forced once again into the center of the low by 25 knot Easterly winds which have plagued the system off and on for days. It sits right in a small pocket of strong shear at the moment and this is evident from the way in which the clouds are oriented and stretched out from the SE to the NW.

Gaston is rapidly closing in on 60 W and once it reaches 63 the odds of regeneration fall historically until 75 W. The only thing going for Gaston that might help him overcome the " John Hope rule " is that the circulation was closed for the past several days and all it lacked was convection. It is difficult to tell whether it is still closed but if not it wouldn't take much to close up again if convection can really fire.

I wouldn't write this one off yet.

The image below shows the pocket of shear I have just mentioned.

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2193. IKE
Looks headed just north of the northern islands.....moving just north of west?

Member Since: June 9, 2005 Posts: 23 Comments: 37858
If it continues north by the next advisory, they're going to have to shift the cone further to the north, and maybe even see a weak cat 1 hurricane before it makes landfall in TX and again that is if the cone shifts further north.
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Morning felllow wunderbloggers!!!,for those of us using mobile phones and don't have access to sat loops(most don't have flash available yet),go to the navy's site and you can get animated loops there,just hit animate and highlight instant,hope this helps someone,i know how much its been driving me crazy as it helps alot to be able to animate sat for us wx junkies,
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2189. tkeith
Quoting IKE:


That's what I'm(as an amateur), thinking.
my non-credentials are well known Ike :)
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Quoting IKE:
Dry air on Gaston....I'd have to lower the odds on him....I'll probably be proven wrong again here in minutes...



The dry air keeps following him. Would they stop picking on him?? LOL
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Quoting IKE:


Somewhere around 17N and 56W...but, it's getting harder to see...even on visible.

It's either opening up or getting filled with weak convection.
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WindSat, in case your interested.
Member Since: August 23, 2008 Posts: 0 Comments: 1918
2185. CATMAN5
What is the system all the models are hinting at for +144 near 18N, 40W --- a future fish storm or real threat? Too far N already for just a 40W long.
No ridge in nw Atlantic?
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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.