ATL: Ex-Tropical Storm GASTON - Discussion

[ConvergenceZone]

The other thing to note is quite probably its track is going to take it very close to Hispaniola, which whilst is a good few days away would also arrest any development, which would therefore make a Gulf/BoC threat pretty much certain...interesting to see a few models move WSW in the Caribbean as well...

Btw, yeah I agree conditions should improve tonight and into tomorrow, even the very bearish global models are showing some strengthening between 24-48hrs before weakening again.

yea, I think Texas needs to keep notice for sure!!! I think if it makes it to gulf that Texas as opposed to florida and LA would be in the path.

[Aric Dunn]

There is absolutely no synoptic evidence this will recurve. the shortwave trough is very weak and not digging. heights are already build across the western atlantic. we can without looking at any maps see that the ridge is strengthening just by noting that gaston has been speeding up on a due west course. if there was any chance for it to miss the islands to the north it would not be speeding up. it will likely go south of PR then maybe as the next trough nears the east coast it might be enough to turn it wnw to NW but there is very little chance of it turning out to sea.

[hurricaneCW]

And once again the convection is falling apart. Looks like it's really picking up speed to. This might have a shot once it gets near 60W but right now it doesn't look good. Definitely not the look of a developing cyclone.

[Aric Dunn]

The other thing to note is quite probably its track is going to take it very close to Hispaniola, which whilst is a good few days away would also arrest any development, which would therefore make a Gulf/BoC threat pretty much certain...interesting to see a few models move WSW in the Caribbean as well...

Btw, yeah I agree conditions should improve tonight and into tomorrow, even the very bearish global models are showing some strengthening between 24-48hrs before weakening again.

if it passes south of the Hispaniola it will very likely survive because its the southerly inflow that needs to be intact.

[cycloneye]

18z Best Track

AL, 09, 2010090518, , BEST, 0, 170N, 512W, 25, 1009, LO

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 010.invest

[KWT]

There is absolutely no synoptic evidence this will recurve. the shortwave trough is very weak and not digging. heights are already build across the western atlantic. we can without looking at any maps see that the ridge is strengthening just by noting that gaston has been speeding up on a due west course. if there was any chance for it to miss the islands to the north it would not be speeding up. it will likely go south of PR then maybe as the next trough nears the east coast it might be enough to turn it wnw to NW but there is very little chance of it turning out to sea.

The interesting thing is some models even take this WSW for a short time and I think as long as it doesn't strengthen too much it'll probably end up missing that weakness totally.

System once again not looking quite so hot, it seems to be having real trouble just holding the convection, instablity must be pretty poor in the region for that to be happening though it is worth noting we are on the downward trend towards Dmin.

[ConvergenceZone]

Man, Ex-Gaston seems like another storm that seems to be struggling.

This September seems normal so far. It sure doesn't seen like a La Nina September filled with insane hyperactivity....

[Aric Dunn]

There is absolutely no synoptic evidence this will recurve. the shortwave trough is very weak and not digging. heights are already build across the western atlantic. we can without looking at any maps see that the ridge is strengthening just by noting that gaston has been speeding up on a due west course. if there was any chance for it to miss the islands to the north it would not be speeding up. it will likely go south of PR then maybe as the next trough nears the east coast it might be enough to turn it wnw to NW but there is very little chance of it turning out to sea.

The interesting thing is some models even take this WSW for a short time and I think as long as it doesn't strengthen too much it'll probably end up missing that weakness totally.

System once again not looking quite so hot, it seems to be having real trouble just holding the convection, instablity must be pretty poor in the region for that to be happening though it is worth noting we are on the downward trend towards Dmin.

Yeah I was mentioning the wsw turn possible a couple days ago and how even if it gains strength it could still stay either west or wsw briefly as it passes through the islands.the ridge is building in quickly at the moment. the current upper environment is not very good for sustained convection but over the next few hours is should quickly improve as it nears the upper trough .

[Bailey1777]

aric it' s just amatter of time wouldn't you say? i mean why would the nhc say conditions are conducive if the environment wasnt going to get better?

[Vortex]

It sure appears now this one is carribean bound..The current and forecasted synoptics would likely keep gaston once passing near guadeloupe just to the south of PR and possible DR. The question then becomes does Gaston turn NW across Haiti/Eastern cuba or shoot for the Yucatan. Also, those untouched carribean waters with a favorable upper air pattern could really blow this storm up once entering the carribean.

[KWT]

Man, Ex-Gaston seems like another storm that seems to be struggling.

This September seems normal so far. It sure doesn't seen like a La Nina September filled with insane hyperactivity....

Yeah its been struggling, I don't think its helping that the general instablity across the Atlantic has plummeted again after Earl slowly weakened as it got close to the E.coast and I think thats got to be at least a small part of the reason why convection has been struggling a little to hold. The models also don't really do much with this system at all, and I've seen quite a few times this season with systems that if the models mainly keep it weak and don't show strengthening that is what tends to happen...clearly there is something that most of the global models are seeing which keeps this one in check but what is it?

That being said I just can't imagine this one getting all the way to say 80-85W and not doing anything at all...

[Vortex]

Btw Aric, you've called this storm pretty accurately so far..What are your thoughts once it nears Haiti or just to the south in terms of direction/intensity?

[Aric Dunn]

aric it' s just amatter of time wouldn't you say? i mean why would the nhc say conditions are conducive if the environment wasnt going to get better?

yeah I said it for the last couple days that once it nears the upper trough axis convection should come back. so in about 10 hours or so we should really see it come back.

[cycloneye]

SAB Dvorak

05/1745 UTC 16.8N 51.1W T1.5/1.5 GASTON

[fasterdisaster]

Convection's actually rising over the center for the first time in days. It does look better than yesterday, though by no means impressive.

http://www.ssd.noaa.gov/goes/east/catl/flash-vis.html

Right now one of Gaston's biggest problems is dry air. There's a good deal of moisture right ahead of him. That plus the shear decreasing makes me think takeoff could begin in about 12 hours.

[Aric Dunn]

Convection's actually rising over the center for the first time in days. It does look better than yesterday, though by no means impressive.

http://www.ssd.noaa.gov/goes/east/catl/flash-vis.html

Right now one of Gaston's biggest problems is dry air. There's a good deal of moisture right ahead of him. That plus the shear decreasing makes me think takeoff could begin in about 12 hours.

although the dry air is an issue... the easterly shear is big issue. there is enough convergence that without the shear convection would probably have held better thus far but any time any convection can organize it gets sheared off.

[Bailey1777]

climatolgy is really a small sample in the big picture i mean in the last 1000 years how many systems have gone west of 85? a bunch i bet

[Aric Dunn]

climatolgy is really a small sample in the big picture i mean in the last 1000 years how many systems have gone west of 85? a bunch i bet

Climatology does not replace current synoptics in forecasting any weather system it is only a guide.

[KWT]

Yeah if you look at the loops Aric the easterly shear is an issue, not sure its going to ease off anytime soon either and so that combined with fairly poor overall general instablity combined with the dry air just isn't allowing convection to hold.

Its 93L in the E/C Atlantic all over again!

[fasterdisaster]

I don't think Hispaniola's going to weaken this one for us. Right now the models are converging to the south of Haiti and the DR.