ATL: Ex-Tropical Storm GASTON - Discussion

[KWT]

There we go now been lowered to 50% and even thqat maybe a little optimistic, I'd be hard pushed given the current set-up aloft which hasn't been good enough over the last 3-4 days for development to go much above 30%...though longer term chances are probably a bit higher then that esp if it does avoid Hispaniola.

[Ivanhater]

There we go now been lowered to 50% and even thqat maybe a little optimistic, I'd be hard pushed given the current set-up aloft which hasn't been good enough over the last 3-4 days for development to go much above 30%...though longer term chances are probably a bit higher then that esp if it does avoid Hispaniola.

I think the recon had much to do with the lowering. However, 50 is still quite high given the unfavorable environment in the next 48 hours, so the NHC still thinks highly if it. I do not expect much until after 48 hours.

[Sambucol]

If ex-Gaston reaches the GOM, it seems reasonable to expect it to intensify. Look at how Hermine has developed quickly and in intensity in very little time. IMO, that indicates the GOM is ripe ground for a wave, TD, or TS to develop into a formidable hurricane, given it has enough time over the Gulf to do so. That's why I'm watching this one closely. If it reaches the Caribbean/GOM, the possibility is there for the development of a storm with which to be contended.

[chrisjslucia]

The difficulty for many people who do try to take an interest in the behaviour of tropical waves through to tropical storms is that if they are not connected to S2K or another such forum, they are reliant on the NHC site or sites that take their data from it - like Storm Carib's model info and mapping. So, when Gaston no longer qualifies for warnings, the general level of data immediately available to the public is greatly reduced. Storm Carib carries the models for track forecast; the same reference allows you to calculate distance and future closest point, but when after 3 days of a red circle it still doesn't qualify as an invest or TD, let alone a TS, then the info is blank.

Perhaps the issue is twofold:
1. the impact of a tropical wave or tropical storm on an island 20 miles by 12 miles or less can be far greater proportionately than on a larger island or continental area. Our concerns (and fears) are therefore slightly different
2. where the forecast %age from the NHC is for strengthening above a certain level, then the model data (which is still being produced but is not so easily accessible) should continue to be pumped out. To find out where Gaston is this week is a struggle if you rely on the NHC site, Storm Carib, Stormpulse etc - as it just doesn't show. Many of us in the Islands rely on Storm Carib and it is our first port of call for info. After Ivan, it was critical in getting aid into and info out of Grenada. But it had no info on the location, possible strength and track of Gaston this week - I assume because it would take that from the NHC.

Maybe those of us who are concerned about this need to take it up with the NHC to see if the info can be provided without panic inducing warnings which may have to be retracted. Support from S2K would be a help in that I'm sure.

[Gustywind]

Ouch Gustywind the conditions really aren't all that great for ole Gaston right now, the fact general instablity right now is below normal in the Atlantic combined with the dry air nearby isn't a combo that is good for keeping a system convective for long enough to deserve an upgrade.

Yeah that seems KWT. Given my untrained eyes of amateur, this thing is lacking of serious deep and strong sustained convection. Let's hope that the drying or dying trend will continue (my own opinion). Meanwhile, tstorms and strong showers are always expected (not really sure it could happen given the latest sat pic) tonight and tommorow for Guadeloupe and the Northern Leewards (always under an yellow alert tonight for a risk of strong showers tstorms).
That will be very good news for the Leewards and the Northern Leewards, to be spare of this suspicious system.
Since last Friday it has continued to fight strongly against the dry air but without much success. Convection has often pulse on/off, like a "yo-yo "close to an upgrade and nothing after. Hope that the next couple of hours should not bring an improving and significant TD. After Earl and Fiona, i tkink honestly that our islands want a gentle break! Right islanders?

Whereas, given the fact that we're in the peak of the season and we all know Mother Nature is always full of surprises... let's continue to follow carefully this feature in case of.

[Gustywind]

000
ABNT20 KNHC 062346
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 6 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

MULTIPLE AIRCRAFT RECONNAISSANCE REPORTS INDICATE THAT THE SURFACE
CIRCULATION ASSOCIATED WITH THE REMNANTS OF GASTON REMAINS POORLY
DEFINED...AND THAT THE SURROUNDING ENVIRONMENT IS ONLY MARGINALLY
CONDUCIVE FOR DEVELOPMENT DURING THE NEXT COUPLE OF DAYS.
THEREFORE...THERE IS A MEDIUM CHANCE...50 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS.
REGARDLESS OF DEVELOPMENT...THIS SYSTEM IS CAPABLE OF PRODUCING
HEAVY SHOWERS AND WIND GUSTS TO TROPICAL STORM FORCE IN SQUALLS AS
IT MOVES OVER THE LEEWARD ISLANDS TONIGHT AND TUESDAY.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER ROBERTS/BRENNAN

[perk]

Yeah convection is weakening though thats to be expected given we are just in Dmin right now, but I think ther eis clearly something preventing this system from holding its convection for any amount of time, I can't remember many times where there hasn't been some sort of outflow boundary being spat out by this system and thats not generally a great sign for development.

Still its wave that will likely be in the W.cAribbean/Gulf...IF this had never been Gaston and was just an invest now...we'd be watching this like a hawk even without any real major model support...and to be fair thats how we should be looking at this one.

KWt i could'nt agree more.The fact that was once a classied system maybe the reason why every time it fluctuate in intensity some are ready to stick a fork in it.If it were a strong wave from the beginning and entering the carribean it would garner alot more attention.

[Gustywind]

[Gustywind]

000
AXNT20 KNHC 070002
TWDAT

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

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

A 1008 MB LOW...REMNANT OF GASTON...IS ABOUT 250 NM E OF THE
NORTHERN LESSER ANTILLES NEAR 17N57W MOVING W NEAR 10 KT.
SATELLITE IMAGERY INDICATES A LOW LEVEL SWIRL REMAINS WITH
SCATTERED MODERATE CONVECTION FROM 16N-18N BETWEEN 58W-60W.
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
TONIGHT. INTERESTS IN THOSE ISLANDS SHOULD MONITOR THE PROGRESS
OF THIS SYSTEM.

CARIBBEAN SEA...
EXPECT...THE REMNANTS OF GASTON TO TRAVERSE THE
LEEWARD ISLANDS OVER THE NEXT 24 HOURS WITH CONVECTION.

$$
FORMOSA

[bvigal]

Gusty, what do you think? TWO "medium chance" or TWD "high chance"? Both at 8pm. OK, now I'm confused, LOL!

[cycloneye]

Aparently, most of that special feature paragrafh is from the 2 PM TWO, instead from the 8 PM one.

[cycloneye]

00z Best Track

AL, 09, 2010090700, , BEST, 0, 175N, 590W, 30, 1008, LO

[Gustywind]

Gusty, what do you think? TWO "medium chance" or TWD "high chance"? Both at 8pm. OK, now I'm confused, LOL!

: Yeah Bvigal, that's why i posted them ... what can i say, confused for the NHC too

[bvigal]

00z Best Track

AL, 09, 2010090700, , BEST, 0, 175N, 590W, 30, 1008, LO

Hasn't moved N much, but is moving faster!
07/00z model fix: 17.5N 59.0W, motion 275 degrees @17kt, wind 30kt, pressure 1008mb.<br>
06/18z model fix: 17.5N 57.2W, motion 275 degrees @15kt, wind 30kt, pressure 1011mb.<br>
06/12z model fix: 17.4N 55.5W, motion 275 degrees @14kt, wind 30kt, pressure 1008mb.<br>
06/06z model fix: 17.2N 53.9W, motion 275 degrees @13kt, wind 30kt, pressure 1008mb.<br>

[cycloneye]

hey Luis. How do the mets there warn for systems such as this during hurricane seson when there is not an advisory from the NHC? Do most people there pay attention to those or is it better coming from the NHC when lots of rain is expected from a wave?

If is a big rain event, the media here are all talking about it and NWS in San Juan release local statements about the expected weather.

[Bailey1777]

michael,
i for one am on the patience side, while gaston is taking longer than i thought to get going again it's survival alone in the environment he has been contending with i think shows us his potential down the line. him staying weak may the gom major problem in the end. l see alot of crow to be served soon and you know who you are.

[bvigal]

Gusty, what do you think? TWO "medium chance" or TWD "high chance"? Both at 8pm. OK, now I'm confused, LOL!

: Yeah Bvigal, that's why i posted them ... what can i say, confused for the NHC too

LOLOL! I'm sure Luis is correct, it was just some left-over text from 2pm. I'm anxiously awaiting NWS/SJU's updated marine and discussion tonight. It looks like you will get the first of the rains in Guadeloupe! Here is new 00z precipitable water, moisture around Gaston and into islands is deeper than it was this morning. It's looking more and more like a rainmaker.

[psyclone]

Dr Knabb was just on TWC and referenced decreasing chances with respect to gaston. i agree. it looks awful. however, it is the heart of hurricane season and every disturbance should be watched.

[bvigal]

hey Luis. How do the mets there warn for systems such as this during hurricane seson when there is not an advisory from the NHC? Do most people there pay attention to those or is it better coming from the NHC when lots of rain is expected from a wave?

If is a big rain event, the media here are all talking about it and NWS in San Juan release local statements about the expected weather.

Artist, the National Weather Service in San Juan does the same tasks as they do on the mainland, year round. Their area of responsibility includes Puerto Rico, and it's islands of Vieques and Culebra, and the US Virgin Islands St. Thomas, St. John, and St. Croix. They are also responsible for local marine forecast for zones which surround those islands and also happen to surround the BVI. The BVI at closest point is only 1/4 mile from St. John! So, here we rely heavily on NWS, 365 days/year.

[supercane]

michael,
i for one am on the patience side, while gaston is taking longer than i thought to get going again it's survival alone in the environment he has been contending with i think shows us his potential down the line. him staying weak may the gom major problem in the end. l see alot of crow to be served soon and you know who you are.

Haven't seen anyone make any wild predictions to merit any crow. Most people are saying that the system is weak now but may have potential later, likely in the western Caribbean. Eating crow also goes the other way with those predicting mayhem. What are your bust and crow criteria?