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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i was looking at he gfs maps for next tuesday when whatever gaston will be. evidently the front that comes thru this weekend is lifting out.per posted image. now the question is will it plow thru CA or mexico? or a bit like opal stalls a bit and waits for the next trof/front.
it was only a few days ago that gaston was going to be a fish.
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2584. Patrap
O Lordy..

LOL
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2582. Hhunter
weather in central texas getting worse ..we just had some rain..in south texas ..family is preparing...
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Igor is not Spanish, French, or English. Slavic in nature.

They've sort of grown beyond those restrictions in years as more and more names are retired.
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Quoting TheDawnAwakening:


You have got to remember, that the only part of your statement I had a problem with is the fact that you said he does not have the ability to be a significant threat. That statement is bogus. Right now you are right because something called dry air is inhibiting development. Dry air equals, no instability present and weak lapse rates. As moisture increases so does the instability present as well as lapse rates. Higher dew point air to the west allows for greater instability and therefore you get your low level lapse rates. Remember hurricanes/tropical storms are different beasts then a land induced thunderstorm. They do not rely so much on the need for updrafts. Low level circulations offer weaker updrafts and therefore are not as intense as land based MCCs. Wind shear is favorable for land based storms, while is a major detriment on tropical cyclones. So lapse rates have a greater affect on land based thunderstorms as they aid in the downdraft of intense wind gusts and the updraft potential of thunderstorms over land. Again moist lapse rates allow moisture to become involved, but moisture has to be present in order for lapse rates to be favorable, so all of his problems come from the lack of moisture or dry air.




I see what you're saying, but I said that right now Gaston doesn't have the chance, and that overall, the chances of Gaston having all the right conditions coming back together to injectit with potential is quite low.

The NHC is giving it a high chance of development, but I am sure they are on board with me about the chances of it becoming a major hurricane are very, very slim.
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Not looking so hot.

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2577. Hhunter
14:46:00Z 26.183N 92.817W 392.5 mb
(~ 11.59 inHg) 7,760 meters
(~ 25,459 feet) - 438 meters
(~ 1,437 feet) From 150° at 11 knots
(From the SSE at ~ 12.6 mph) -15.0°C
(~ 5.0°F) -16.0°C
(~ 3.2°F) 12 knots
(~ 13.8 mph

recon flying in...
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Quoting CajunTexan:
Hermine looks like he wants to become a hurricane before making landfall. He just might make it too.


When is Gaston projected to be at around 60W???

Just curious, as that is StormW's benchmark to know more about what Gaston is gonna do.
Uh yeah Hermine is a she...
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RE: Gaston from the NHC 8:00 discussion -


Upper level winds are expected to become more conducive for development over the
next day or so and the moisture surrounding the low should
gradually increase as it moves W at 10-15 kt. There is a high
chance of this system becoming a tropical cyclone again during
the next 48 hours. Heavy rains and gusty winds could begin to
affect portions of the Leeward Islands late today and tonight.

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It looks like the models begin intensifying Gaston in another 24 hours or so, with some more rapid then others.
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Nailed this one?


It ain't over till its over.
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Quoting dan77539:


Anyway, here's hoping we never get to "V" anyway.


Here, here!
Member Since: September 6, 2009 Posts: 2 Comments: 3712
Does anyone know the conversion between 10-min sustained winds and 1-min?
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Hermine looks like he wants to become a hurricane before making landfall. He just might make it too.


When is Gaston projected to be at around 60W???

Just curious, as that is StormW's benchmark to know more about what Gaston is gonna do.
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Quoting dan77539:
5-7 pm seems a little early for landfall...some of that "motion" was a re-positioning of the center...but 11p-2a seems reasonable.


We shall see.
Member Since: September 6, 2009 Posts: 2 Comments: 3712
Quoting ElConando:


Don't forget about LA people of French origin there.


Anyway, here's hoping we never get to "V" anyway.
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Quoting markot:
storm have you seen latest pics of gaston...


today may be gaston's day.
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2563. Kibkaos
Quoting Hhunter:


Hermine is growing quickly. I am down here in Brazoria County South of Houston and the clouds and rain are rolling in.
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No offence,and some of you may put me on ignore,but trying to watch Gaston redevelope has been like trying to watch paint dry on a wall.Just saying.....
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Quoting dan77539:


Since not everyone in the Atlantic basin speaks English, they like to throw some French & Spanish names out there. French is for Haiti, and a few of the Lesser Antilles that were French colonies. And Virginie (VEER - zhee - NEE) is French for "Virginia".


Don't forget about LA people of French origin there.
Member Since: September 6, 2009 Posts: 2 Comments: 3712
160 knots or 19.

Thats quite a spread.

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5-7 pm seems a little early for landfall...some of that "motion" was a re-positioning of the center...but 11p-2a seems reasonable.
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Quoting IKE:
Landfall should be this evening...by midnight.

I agree....coordinates on their track look a little slow.


Yeah that has me perplexed at the 11AM advisory. Oh well. I guess we will have a better idea when the HH get in there.
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2556. markot
storm have you seen latest pics of gaston...
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Quoting Jedkins01:



Or they just got bored and decided to put a little ole southern draw into the spelling of virginia, lol.


Since not everyone in the Atlantic basin speaks English, they like to throw some French & Spanish names out there. French is for Haiti, and a few of the Lesser Antilles that were French colonies. And Virginie (VEER - zhee - NEE) is French for "Virginia".
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2554. Hhunter
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Quoting StormW:


???
By people on the blog.
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Hermine will probably hit at 11 pm tonight.
Member Since: July 8, 2005 Posts: 259 Comments: 23927
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Quoting Jedkins01:



Gaston hasn't developed convection throughout its life time, that would equal an afternoon sea breeze convective flare up in Florida, how much more ridiculous then would it to be to consider a model which attains it to category 5 intensity.


Keep in mind, Physics do just not support Gaston becoming anything significant right now.

I did mention nothing is impossible, but the chances are quite minute indeed. Therefore, Gaston should not be worried about.

The atmosphere would have to change radically throughout Ex-Gaston for it to have a chance at significant development into a strong hurricane. The chance of this happening, is very very low.

Not only is moisture lacking, but lapse rates are extremely weak around it, and overall instability just plain sucks.


You have got to remember, that the only part of your statement I had a problem with is the fact that you said he does not have the ability to be a significant threat. That statement is bogus. Right now you are right because something called dry air is inhibiting development. Dry air equals, no instability present and weak lapse rates. As moisture increases so does the instability present as well as lapse rates. Higher dew point air to the west allows for greater instability and therefore you get your low level lapse rates. Remember hurricanes/tropical storms are different beasts then a land induced thunderstorm. They do not rely so much on the need for updrafts. Low level circulations offer weaker updrafts and therefore are not as intense as land based MCCs. Wind shear is favorable for land based storms, while is a major detriment on tropical cyclones. So lapse rates have a greater affect on land based thunderstorms as they aid in the downdraft of intense wind gusts and the updraft potential of thunderstorms over land. Again moist lapse rates allow moisture to become involved, but moisture has to be present in order for lapse rates to be favorable, so all of his problems come from the lack of moisture or dry air.
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I would agree with Cotillion 5-7 pm could be around the time it could make landfall.
Member Since: September 6, 2009 Posts: 2 Comments: 3712
2547. IKE
Landfall should be this evening...by midnight.
Quoting Cotillion:
INITIAL 06/1500Z 23.4N 95.8W 45 KT
12HR VT 07/0000Z 24.9N 96.9W 60 KT
24HR VT 07/1200Z 27.0N 98.3W 55 KT...INLAND

Unless it slows down some, there's no way it's still going to be over water in 12 hours.

At current speeds, more like 6.



I agree....coordinates on their track look a little slow.
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2546. Patrap
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Landfall could be a bit at 5pm imo.
Member Since: September 6, 2009 Posts: 2 Comments: 3712
INITIAL 06/1500Z 23.4N 95.8W 45 KT
12HR VT 07/0000Z 24.9N 96.9W 60 KT
24HR VT 07/1200Z 27.0N 98.3W 55 KT...INLAND

Unless it slows down some, there's no way it's still going to be over water in 12 hours.

At current speeds, more like 6.

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Quoting IKE:


Moved .8N and .4W again in 3 hours. Landfall will be sooner than first thought.


Definitely.

THE INITIAL MOTION IS 340/11...A LITTLE FASTER THAN BEFORE. HERMINE
IS EXPECTED TO CONTINUE MOVING NORTH-NORTHWESTWARD WITH A SLIGHT
INCREASE IN FORWARD SPEED AS THE STORM MOVES ALONG THE WESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE. THE LATEST NHC TRACK FORECAST
IS A LITTLE FASTER THAN THE PREVIOUS ON
E AND IS FAIRLY CLOSE TO THE
MULTI-MODEL CONSENSUS.

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2539. Patrap
000
WTNT35 KNHC 061431
TCPAT5
BULLETIN
TROPICAL STORM HERMINE ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102010
1000 AM CDT MON SEP 06 2010

...HERMINE STRENGTHENS A LITTLE MORE...NEW WATCHES AND WARNINGS
ISSUED...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.4N 95.8W
ABOUT 130 MI...210 KM ESE OF LA PESCA MEXICO
ABOUT 205 MI...325 KM SSE OF BROWNSVILLE TEXAS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/HR
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 13 MPH...20 KM/HR
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE GOVERNMENT OF MEXICO HAS ISSUED A HURRICANE WATCH FROM RIO SAN
FERNANDO NORTHWARD TO THE MOUTH OF THE RIO GRANDE...AND A HURRICANE
WATCH HAS BEEN ISSUED FROM THE MOUTH OF THE RIO GRANDE NORTHWARD TO
BAFFIN BAY TEXAS.

THE TROPICAL STORM WARNING HAS BEEN EXTENDED NORTHWARD TO PORT
OCONNOR.

THE GOVERNMENT OF MEXICO HAS DISCONTINUED THE TROPICAL STORM WARNING
SOUTH OF LA CRUZ.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* RIO SAN FERNANDO MEXICO NORTHWARD TO BAFFIN BAY TEXAS

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* LA CRUZ MEXICO NORTHWARD TO PORT OCONNOR TEXAS

A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA...IN THIS CASE WITHIN ABOUT 24 HOURS.

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN
ABOUT 24 HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE
THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.
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HH into HerMean


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THE INITIAL MOTION IS 340/11...A LITTLE FASTER THAN BEFORE. HERMINE
IS EXPECTED TO CONTINUE MOVING NORTH-NORTHWESTWARD WITH A SLIGHT
INCREASE IN FORWARD SPEED AS THE STORM MOVES ALONG THE WESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE. THE LATEST NHC TRACK FORECAST
IS A LITTLE FASTER THAN THE PREVIOUS ONE AND IS FAIRLY CLOSE TO THE
MULTI-MODEL CONSENSUS.

Good news for potential flood threat to S Tx/N Mex
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looks like Hermine has been underestimated.The NHC knows what their dealing with when it comes to systems like these.....
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Quoting alaina1085:

Im pretty sure that state is VirginIA...lol
I think they combined virgin with virginia and popped out a name... are they getting that desperate?



Or they just got bored and decided to put a little ole southern draw into the spelling of virginia, lol.
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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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