ATL: Tropical Depression Fay

[SouthFloridawx]

This system is sitting under a favorable upper level conditions.

[Scorpion]

Well it seems like it should finally get its act together tomorrow. Not holding my breath though.

[Gustywind]

Atlantic Tropical Weather Discussion
--------------------------------------------------------------------------------


000
AXNT20 KNHC 120557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE AUG 12 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.
..SPECIAL FEATURES...
A TROPICAL WAVE LOCATED OVER THE CENTRAL ATLANTIC ALONG 49W/50W
OR ABOUT 650 NM EAST OF THE LESSER ANTILLES IS SUPPORTING AN
AREA OF ORGANIZED SCATTERED SHOWERS AND THUNDERSTORMS FROM
14N-19N BETWEEN 46W-53W. A 1007 MB LOW IS EMBEDDED ON THE WAVE
AXIS NEAR 13N. CONVECTIVE ACTIVITY HAS BEEN COME BETTER
ORGANIZED OVER THE PAST 6-12 HOURS AND ENVIRONMENTAL CONDITIONS
APPEAR FAVORABLE FOR GRADUAL DEVELOPMENT OF THE SYSTEM WHICH HAS
THE POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT
COUPLE OF DAYS AS IT MOVES WEST-NORTHWESTWARD AT 15 KT.

[bvigal]

And from TWO, forecastor Rhome:

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT TUE AUG 12 2008

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

A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
LOCATED OVER THE CENTRAL ATLANTIC OCEAN ABOUT 750 MILES EAST OF
THE LESSER ANTILLES. ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY
HAS BEEN GRADUALLY INCREASING...AND A TROPICAL DEPRESSION COULD
FORM DURING THE NEXT DAY OR SO AS THE SYSTEM MOVES WEST-
NORTHWESTWARD AT ABOUT 15 MPH. AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM ON
TUESDAY...IF NECESSARY.
... (more on 93 and W Caribbean)

[Gustywind]

And from TWO, forecastor Rhome:

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT TUE AUG 12 2008

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

A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
LOCATED OVER THE CENTRAL ATLANTIC OCEAN ABOUT 750 MILES EAST OF
THE LESSER ANTILLES. ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY
HAS BEEN GRADUALLY INCREASING...AND A TROPICAL DEPRESSION COULD
FORM DURING THE NEXT DAY OR SO AS THE SYSTEM MOVES WEST-
NORTHWESTWARD AT ABOUT 15 MPH. AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM ON
TUESDAY...IF NECESSARY.
... (more on 93 and W Caribbean)

Tkanks bvigal

[bvigal]

You too, Gustywind! I'm going back to bed for a couple more hours of sleep.

[carolina_73]

Not looking too bad...

[Meso]

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

Looking at the visible loop (Not for a centre since it's dark, obviously), convection continues to fire on the Southern side while the system looks to be getting sheared a bit.Which would make sense looking at the graphic below where it shows the system hitting the end of a 30kt shear area.



Further more, dry air continues to block it's path and with the shear it is likely the reason why the system seems to be struggling, once it passed the area of shear the environment becomes a bit less hostile, as the dry air is less dense near 'The Islands' it should have a better chance at maintaining itself

[xironman]

I agree that the shear is starting to get to it a bit and displacing convection, but from staring at the central Atlantic IR2, since the floater shortwave is useless, I would put the "center" back around 15N 50W which should be in the envelope enough to protect it from that dry air.

[KWT]

Once again 92L is getting a little les soprganised. Convection however is still flaring up near with the invest though there doesn't appear to be any circulation with it, at least at the surface anyway. Still a new pulse of convection formed where the estimated circulation is right now.

[Jam151]

Am I the only one that sees a circulation that is at the very least located in the mid-levels exactly where the convection is firing? It's very obvious on the shortwave. If so I don't understand all the "less organized this morning" talk. Sure there's southerly shear impinging on it. We all knew that's gonna be the case for a while. But nevertheless, we have convection over the center AND additional convection to the south and west....pretty good in a slight southerly shear environment.

[KWT]

Maybe though I think its just the way the convection is exanpding from that deeper burst that makes it look like a circulation is there.

That convection however is probabloy located near the greatest Voricity right now.

[xironman]

You are not alone, the RAMSDIS loop http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_4km_visir2_floater_1 even shows it better. The southern inflow looks much better and clearly curving around the area.

[KWT]

Actually I can see what your talking about now, I'd guess its at mid levels just in front of that deep convection...lets see if it keeps this circulation for more then 6hrs this time

Convection expanding over the circulation, also should get the first Vis.images pretty soon.

[Jam151]

Thanks for the input and links guys. Early morning visibles should be interesting if this persists!

[KWT]

Yep indeed, will be interesting to see if it holds for when recon goes into the system because if the convection doesnt get sheared away before then may well see interesting reports from recon.

[xironman]

My guess is no recon today, still too far east and a bit too disorganized to push it. They can tell remotely that they have a developing system and act appropriately while waiting for 92L to get a bit closer.

[carolina_73]

If the circulation is located near that deep red blob then this system could really get going for a change.

[KWT]

IMO circulation is probably just west of the deepest of that convection but that big burst does seem to have come from the western side of that circulation which is helping to keep it going.

[wxman57]

Buoy observations at 14.5N/53W (ENE 10 kts / 1009.7mb) and 14.5N/46W (SE 10 kts / 1010.7mb) suggest this is just an open wave - no circulation center. That western buoy, by the way, has a wind blowing directly away from that heaviest blob of convection. Not exactly a sign that there is any LLC near the convection. I haven't seen a circulation center evident on satellite since yesterday morning. Convection is too limited to generate much inflow. No development today, most likely.