ATL GUSTAV: Tropical Depression - Discussion

[cycloneye]

ABNT20 KNHC 211754
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT THU AUG 21 2008

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM FAY...CENTERED NEAR THE EAST COAST OF FLORIDA CLOSE TO FLAGLER
BEACH.

SHOWER ACTIVITY ASSOCIATED WITH AN AREA OF LOW PRESSURE LOCATED
ABOUT 850 MILES EAST OF THE WINDWARD ISLANDS REMAINS DISORGANIZED.
DEVELOPMENT...IF ANY...OF THIS SYSTEM IS EXPECTED TO BE SLOW TO
OCCUR AS IT MOVES TO THE WEST-NORTHWEST AT ABOUT 15 MPH.

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

$$
FORECASTER BLAKE

[KWT]

Convection is indeed still strngethening but on the NW side of any circulation, the center appears to be more on the eastern side of the system, would guess there is some SE shear on the system right now.

[Gustywind]

AXNT20 KNHC 211756
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU AUG 21 2008

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

A SMALL 1008 MB LOW IS ANALYZED IN THE CENTRAL ATLC NEAR 12N47W
MOVING W NEAR 10-15 KT. SCATTERED MODERATE TO STRONG CONVECTION
IS OBSERVED W OF THE LOW FROM 11N-14N BETWEEN 47W-53W.

[cheezyWXguy]

Shear is still affecting the storm, but conditions are already starting to become more favorable for convective development, as convection has stuck around for a bit longer than the last 2 days. In addition, WV loop shows the ULL beginning to move away, now towards the wnw a bit faster than 94L is moving. The TWO may show little development over the next 2 days, but after that, development looks more likely with increasingly favorable conditions.

[cycloneye]

Definitly 94L has to be watched closely.

[KWT]

cheezyWXguy, yeah I agree conditions are starting to improve, convection mainly devloping a little to the west and north of the so called center but that will jump about quite a lot so we shall see, for now I suspect we are still a good 48-72hrs away from development but conditions should slowly continue to improve as the ULL moves out of the way slowly but surely.

[cycloneye]

The 18:00 UTC Best Track:

L, 94, 2008082118, , BEST, 0, 122N, 488W, 25, 1007, LO, 34,

[KWT]

Convection decreasing for Dmin again though there is some convectin over the best track center at least which is interesting, just needs to last a while longer till it gets towards the much better conditions.

[Gustywind]

21/1745 UTC 12.3N 48.6W TOO WEAK 94L -- Atlantic Ocean

[KWT]

Not all that surprisig given how all the convection is mainly west and quite a bit west of that as well but that may well be caused by the shear.

Also what is the convergence like, has it shifted east I wonder?

[cheezyWXguy]

Not all that surprisig given how all the convection is mainly west and quite a bit west of that as well but that may well be caused by the shear.

Also what is the convergence like, has it shifted east I wonder?

I think its more that the circulation remains elongated, as opposed to exposed. Based on visible loops i can see that the center is inside the convection, tho convection is weakening right now. However this is the most persistent convection has been since it was first declared invest, so conditions are gradually improving. Shear is still obviously impacting the storm, but I expect the shear to die off in 24 hours or less, leading to possible development in about 2 days.

[Dean4Storms]

Two surfers got out at Jax. Bch, one drowned and the other is injured.

Mayport reported a 61mph gust.

Jax NAS Gust to 58mph, that is inland a good bit, maybe 20 miles but along the St. Johns River.

[Dean4Storms]

Wow, Tybee Island near Savannah has sustained winds near 35mph and gusts to 43mph. That is a big wind field and the pressure gradient is coming into play now. She just may keep some strong winds with the gradient setting up. They probably will raise TS Warnings for the NE GOM before it is over.

[ConvergenceZone]

Because of how aggresive a couple of the models are with this, this really has my attention...I too believe that the reason the TWO and Jeff Masters isn't bullish on this wave is because of the shear. I think they will become increasingly bullish in about 3 days however

[KWT]

Yeah by the time this gets to around 60W conditions do improve. Till then its jsut going to flare up then flare down again just like its doing right now, pretty bog standard stuff.

[abajan]

Wow, right now 94L looks in pretty poor shape. It will be interesting to see how much convection re-fires tonight.

[cheezyWXguy]

Wow, Tybee Island near Savannah has sustained winds near 35mph and gusts to 43mph. That is a big wind field and the pressure gradient is coming into play now. She just may keep some strong winds with the gradient setting up. They probably will raise TS Warnings for the NE GOM before it is over.

Two surfers got out at Jax. Bch, one drowned and the other is injured.

Mayport reported a 61mph gust.

Jax NAS Gust to 58mph, that is inland a good bit, maybe 20 miles but along the St. Johns River.

Youre in the wrong thread.

[KWT]

Yep 94L looks pretty terrible now but thats to be expected given we are in Dmin however thats ba good sign this won't develop anytime soon, as whilst you should expect convection to weaken in Dmin it should completely go poof like this, i remember pre Fay and Dolly did similar things in the first stage of development.

[cycloneye]

701
ABNT20 KNHC 220000
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT THU AUG 21 2008

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM FAY...CENTERED NEAR THE NORTHEAST COAST OF FLORIDA CLOSE TO
FLAGLER BEACH.

SHOWER ACTIVITY HAS DECREASED THIS EVENING IN ASSOCIATION WITH AN
AREA OF LOW PRESSURE LOCATED ABOUT 750 MILES EAST OF THE WINDWARD
ISLANDS. HOWEVER...ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME
MORE CONDUCIVE FOR SLOW DEVELOPMENT OF THIS SYSTEM DURING THE NEXT
COUPLE OF DAYS AS IT MOVES WESTWARD OR WEST-NORTHWESTWARD AT ABOUT
15 MPH.

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

$$
FORECASTER BROWN/KNABB

[Blown Away]

The TAFB keeps 94L with the low through 72 hours and puts the low near PR & Hispanola, earlier the TAFB dissipated the low after 24 hours.
http://www.nhc.noaa.gov/tafb_latest/atl ... BW_sm3.gif