ATL: Tropical Depression Fay

[deltadog03]

The inflow also looks much better this morning than yesterday. I invite you to look at the loops and turn on the high/upper winds. It appears** that the upper level winds are beginning to weaken.

[N2Storms]

The Tallahassee NWS has changed their tune since yesterday on the potential impact that 92L may have on our area. Yesterday they mentioned the Tropical Wave would need to be watched closely but today, not so much.




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000
FXUS62 KTAE 131336
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
935 AM EDT WED 13 2008

.SUN-WED. IT WILL BECOME INCREASINGLY MUGGY AS THE SUBTROPICAL RIDGE
BUILDS WESTWARD AND GULF MOISTURE ADVECTS NORTHWARD AROUND THE WEST
SIDE OF THE UPPER RIDGE...WITH MANY AREAS REMAINING AT OR ABOVE 70
AT NIGHT. WITH HIGH PRESSURE DOMINATING...POPS WILL DROP TO BELOW
CLIMO. ANY PRECIPITATION WILL BY DRIVEN BY DIURNAL HEATING AND
AFTN/EVENING SEA BREEZES. IN ADDITION...A TROPICAL WAVE MOVING
THROUGH THE BAHAMAS AND S FL TUES-WED WILL LIKELY NOT HAVE MUCH
AFFECT ON THE SENSIBLE WEATHER IN THE FORECAST AREA.

[cycloneye]

The latest visible image:

[Stormcenter]

outflow boundary out of the convection to the north

expecting this convection to die off in the next 3-6 hours

Derek I know things can change but as of now what's you gut feeling on this one?

[CrazyC83]

Solid convection, but clearly no circulation.

[wxman57]

Here's another graphic you may find interesting. I plotted the 00Z GFS surface pressure valid for 12Z Wednesday, August 20th in 0.25mb increments. On top of that, I plotted the 700mb-400mb (10,000-20,000 ft) mean wind flow valid for the same time. By next Wednesday, the GFS has 92L in the FL Straits with very weak west winds aloft. So if the GFS is correct, it may be moving very slowly westward through the Fl Straits next Tue-Wed. I realize 7 days out with the GFS is a big "if", but it looks like a reasonable forecast. Where it goes once it's in the Gulf is the big question.

[MWatkins]

The inflow also looks much better this morning than yesterday. I invite you to look at the loops and turn on the high/upper winds. It appears** that the upper level winds are beginning to weaken.

Good point. The low clouds to the SW and south of the convection were moving southward...away from the feature we were tracking yesterday. Today they are streaming northward toward the convection.

I have little doubt there is some low to the west of the thunderstorms, but the wave axis is supporting the new ones...no doubt this is the feature to watch (I think) as we get toward the weekend.

MW

[Steve]

>>And if it does develop into a TS, then I don't see much to stop it from becoming a hurricane and a threat to the Gulf in about 7 days.

See what you and the Tally NWS are saying, but that would require some ridging to the north of the system. The ridge it's riding now is somewhat eliptical and long. Also see the streaming clouds S to N about 100 miles ahead of the system. Based on the banding (right parenthesis), looks like inflow into a concentric upper low centered around Haiti and retrograding. Not sure about the "Gulf" at this point though. Maybe. Predicting the upper environment and steering 5 days out is kind of tough. I'd give it equal chances of a SE FL problem as the primary or at least initial threat-watch area for now. Thanks as always 57 (and Sunny and Stormcenter).

Steve

[Stormcenter]

Here's another graphic you may find interesting. I plotted the 00Z GFS surface pressure valid for 12Z Wednesday, August 20th in 0.25mb increments. On top of that, I plotted the 700mb-400mb (10,000-20,000 ft) mean wind flow valid for the same time. By next Wednesday, the GFS has 92L in the FL Straits with very weak west winds aloft. So if the GFS is correct, it may be moving very slowly westward through the Fl Straits next Tue-Wed. I realize 7 days out with the GFS is a big "if", but it looks like a reasonable forecast. Where it goes once it's in the Gulf is the big question.

Will there possibly be a blocking ridge to the north of 92L steering it across the GOM?

[Steve]

Wow. Thanks for the future-plot 57. That's what I was talking about Monday morning on the 93L thread. Still not sure how far west 93L is going to get, but I like the idea of a farther north and east threat than the one presented by 92L. Said I thought 93L had the bigger end-game potential too, but I'm going to wait and see before talking more about that.

Steve

[Sanibel]

You are going to have trouble getting that convection center to maintain a Low if the weak circulation center crashes on the islands. Guess nobody is interested in the obvious. Especially in shear. The only chance 92 has on this track is a healthy reconvecting and center shift north of the major islands.

[tolakram]

You can see the outflow boundaries in this image, NW of the blob.

[Steve]

>>Will there possibly be a blocking ridge to the north of 92L steering it across the GOM?

On that chart, mean flow is SSE-NNW across the central/western Gulf. Not sure if that would be the steering layer at that point (e.g. what are we dealing with if there's a slow moving system sitting on 85+/- degree water). Interesting possibilites.

>>You are going to have trouble getting that convection center to maintain a Low if the weak circulation center crashes on the islands. Guess nobody is interested in the obvious. Especially in shear. The only chance 92 has on this track is a healthy reconvecting and center shift north of the major islands.

I say just watch it and give it time. We'll know more by Friday whether it looks like a crash and burner or if it's going to make a run at development. Right now, we'll just see some up and down pulses in convective activity. JMO

Steve

[Canelaw99]

The blob now appears to be moving westward. Right?

Yes,and I like that to continue moving this way,as we can get plenty of rain here to terminate the drought.

Don't worry Cyc...I'm going to PR the end of next week and (ask my husband's abuela) I am known in his family for bringing torrential rains. LOL We were there in '05 (katrina time) and had quite a bit of rain, as we did in Jan. of that same year. I'll do what I can for you guys LOL

Back on topic: I am definitely keeping tabs on this potential threat, as my bday is Monday and I don't need any unexpected visitors at the party LOL

[Extremeweatherguy]

The GFS forecast looks pretty good, but I doubt it will take until Wednesday to reach that area. Considering 92L is already quickly approaching 60W, I think the system will probably be in the vicinity of 80-82W by Tuesday, not Wednesday. The model consensus seems to agree right now too, and has this system already near 78W by 12z Monday: https://my.sfwmd.gov/sfwmd/common/image ... orm_92.gif

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.

[Ed Mahmoud]

Here's another graphic you may find interesting. I plotted the 00Z GFS surface pressure valid for 12Z Wednesday, August 20th in 0.25mb increments. On top of that, I plotted the 700mb-400mb (10,000-20,000 ft) mean wind flow valid for the same time. By next Wednesday, the GFS has 92L in the FL Straits with very weak west winds aloft. So if the GFS is correct, it may be moving very slowly westward through the Fl Straits next Tue-Wed. I realize 7 days out with the GFS is a big "if", but it looks like a reasonable forecast. Where it goes once it's in the Gulf is the big question.

If (and I know its a big if) that mean flow doesn't change, it'll slowly turn Northwest, then almost due North, won't it?

[artist]

have you all seen what senor pepr did for us re this storm?

viewtopic.php?f=59&t=102471

[Stormcenter]

Here's another graphic you may find interesting. I plotted the 00Z GFS surface pressure valid for 12Z Wednesday, August 20th in 0.25mb increments. On top of that, I plotted the 700mb-400mb (10,000-20,000 ft) mean wind flow valid for the same time. By next Wednesday, the GFS has 92L in the FL Straits with very weak west winds aloft. So if the GFS is correct, it may be moving very slowly westward through the Fl Straits next Tue-Wed. I realize 7 days out with the GFS is a big "if", but it looks like a reasonable forecast. Where it goes once it's in the Gulf is the big question.

If (and I know its a big if) that mean flow doesn't change, it'll slowly turn Northwest, then almost due North, won't it?

What are you getting at Ed? I personally still have doubts 92L will even make it into the GOM.

[Canelaw99]

great job senor!!! Thanks a bunch

[Steve]

>>What are you getting at Ed? I personally still have doubts 92L will even make it into the GOM.

Think he's just throwing out the caveat that if the GFS is right in the 7 day period, this is what things will look like. He also acknowledged that trust in the GFS at that period is suspect at best. That's what I got from it anyway.

Steve