ATL: Ex-Tropical Storm GASTON - Discussion

[cycloneye]

Up to 80%

TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN SEP 5 2010

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

SHOWER AND THUNDERSTORM ACTIVITY HAS BECOME BETTER ORGANIZED IN
ASSOCIATION WITH THE REMNANT LOW OF GASTON LOCATED ABOUT 700 MILES
EAST OF THE LEEWARD ISLANDS. ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD
REDEVELOP INTO A TROPICAL DEPRESSION AT ANY TIME TODAY OR TONIGHT
AS IT MOVES WESTWARD NEAR 15 MPH. INTERESTS IN THE LEEWARD ISLANDS
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. WARNINGS WILL LIKELY
BE REQUIRED FOR SOME OF THESE ISLANDS IF ADVISORIES ARE
RE-INITIATED. THERE IS A HIGH CHANCE...80 PERCENT... OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS.

[Sanibel]

Sanibel, September (the first few weeks at least) has historically produced Cape Verde systems that have impacted Southern FL from the SE. So it's not really August-like at all (though end of August is another time where Cape Verde systems have impacted Southern FL from the east).

Well the context was WX57 saying climatology would make a US-landfalling cyclone very rare from this position. So, yes, what you say is correct and there are many direct CV trackers right into Florida in this climatology however I think the August reference made by x-y-no was implying the East Coast High was more likely earlier in the season.

My personal feeling is Gaston is showing the beginning of development that won't stop. However track and synoptics could override that and knock it down still.


.

[Aric Dunn]

there is a little more low level thickening of the clouds could begin to see more convection as the upper environment improves throughout the day.

[hurricaneCW]

It still looks kind of sheared and the convection remains disorganized. I think maybe the NHC will up the percentage to 80 or keep it at 70.

[Aric Dunn]

It still looks kind of sheared and the convection remains disorganized. I think maybe the NHC will up the percentage to 80 or keep it at 70.

yes still some easterly shear but should decrease and become more divergent over the next 10 hours or so.

[Sanibel]

If you look closely one of the east quadrant bands shot some convection that was then blown by the easterly shear right across the center. This probably means there's a strong High guiding Gaston which would make more west tracks plausible.

I think it's on because Gaston just blew convection from its dry east band.

[Bailey1777]

imo it is just the starting line of what i said last night would be a memorable ride. short of the islands tearing it up i think this will make those questioning it into believers. this one is a sneaker get it...IMO

[KWT]

What will be interesting is to see just how close to due wes tit tracks, its quite possible this one takes a track like Georges but a weaker version of it and go through the islands but we will see...

Anything too strong will recurve, but if it stays weak enough until 65-70W then things will get really interesting and the threat levels will shoot through the roof.

[wjs3]

Looks like outflow/arc clouds got barfed out in the last few frames. Lots of dry air still.

I agree there's a touchhhh too much easterly shear right now for convection to really consolidate. Needs more time.

[Bailey1777]

it will be fine. nhc sees a conducive environment. td at 11 IMO. the longer it takes now to really ramp up will be a gain for itself later.IMO

[gone2beach]

It still looks kind of sheared and the convection remains disorganized. I think maybe the NHC will up the percentage to 80 or keep it at 70.

They are showing 80% now.


http://www.nhc.noaa.gov/gtwo/gtwo_atl_s ... 1#contents

Return to Atlantic Graphical TWO
1. SHOWER AND THUNDERSTORM ACTIVITY HAS BECOME BETTER ORGANIZED IN
ASSOCIATION WITH THE REMNANT LOW OF GASTON LOCATED ABOUT 700 MILES
EAST OF THE LEEWARD ISLANDS. ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD
REDEVELOP INTO A TROPICAL DEPRESSION AT ANY TIME TODAY OR TONIGHT
AS IT MOVES WESTWARD NEAR 15 MPH. INTERESTS IN THE LEEWARD ISLANDS
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. WARNINGS WILL LIKELY
BE REQUIRED FOR SOME OF THESE ISLANDS IF ADVISORIES ARE
RE-INITIATED. THERE IS A HIGH CHANCE...80 PERCENT... OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS.


*Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Dean4Storms]

There is still some mid-level shear affecting Gaston, I believe 15-20kts.

http://cimss.ssec.wisc.edu/tropic/real- ... idshr.html

He'll reach a better environment throughout the day and he could pop tonight.

As far as the future track for Gaston.....It is much too early to speculate beyond a likely track into the NE Islands, from there much will depend on the depth of the trough and the depth and position of Gaston.

[KWT]

That wouldn't be a great sign for development wjs3, this system does seem to be struggling not so much with just dry air but with a general lack of instablity which has once again fallen upon the Atlantic in general...

Still if it does get held back that sure will make things more complicated for alot of people down the line, esp for possibly the W.Caribbean countries, Mexico and the Gulf states...

[Dean4Storms]

He's also contending with a bit of upper level shear.......but it lessens as he moves west today.

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

[Aric Dunn]

That wouldn't be a great sign for development wjs3, this system does seem to be struggling not so much with just dry air but with a general lack of instablity which has once again fallen upon the Atlantic in general...

Still if it does get held back that sure will make things more complicated for alot of people down the line, esp for possibly the W.Caribbean countries, Mexico and the Gulf states...

The environment will quickly become more conducive aloft as it approaches the islands. When it nears the upper trough the easterly shear will begin to shift and become more southerly and more divergent which will aid convection and the atmosphere becomes a little less dry. later tonight we should see convection come back.

[Bailey1777]

kwt that's kinda my thought even if this guy stays at the level it is now for 72hrs the effect onit's heading and future strenth because of staying weak will be way more dangerous.IMO

[wjs3]

Agreed, Aric. I was impressed with the blowup earlier today--clearly still lots of vorticity/convergence there, but I think--as you do--that it's early to classify. Don't think it will really sustain this burst.

I also agree that the upper pattern starts to look better a bit down the road.

KWT, yes, the arc clouds/outflow are not a good sign for development, but, as you know, very typical for the environment Gaston is in.

[Gustywind]

What will be interesting is to see just how close to due wes tit tracks, its quite possible this one takes a track like Georges but a weaker version of it and go through the islands but we will see...

Anything too strong will recurve, but if it stays weak enough until 65-70W then things will get really interesting and the threat levels will shoot through the roof.

not a good memory Georges

[ConvergenceZone]

I think if it doesn't recurve, then it may make it all the way to Texas.....

Also, notice that the NHC said "warnings" for the islands as opposed to "watches"? They obviously think that this may go over the islands instead of north of the islands.

[KWT]

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.