ATL: TROPICAL LOW ex-FRED (ex-07L)

[Aric Dunn]

well eclipse time again.. which means sleep .

The 11:30 PM sat. photo suggests warming of the coldest cloud tops. However, the overall area of convection seems to be spreading out/growing in size all around the area of lowest pressure. So, I can't tell that this is necessarily a sign that the convection is pretty much going to go poof. Any other opinions? Aric, before you hit the sack, any comments? Otherwise, good night.

I pretty sure what we see with the convection recently is not much weakening of the shear rather just becoming more divergent which is helping convection. if you look at the upper flow on WV the trough over the US is pulling NNE and we have a ull over the southern gulf that has been in part the problem with the shear. but the trough lifting out has shifted the flow or split it a little making it more divergent. GFS weakens the shear down to 10kts tomorrow evening and is more divergent as well. Not saying it will develop but it is probably going to be its last chance..

[Aric Dunn]

Before u go Aric, what's that in the GOM?

looks like a old boundary left over.. would not worry too much about it..

[deltadog03]

To elab on what Aric said

[IvanSurvivor]

Thanks...Good Night!

[LarryWx]

Is shear best estimated by looking at 300 mb or is it better to look at 200 mb maps? Anyone? Thanks.

[Aric Dunn]

Is shear best estimated by looking at 300 mb or 200 mb maps? Anyone? Thanks.

well really from all layers.. its calculated through all layers but typically the 200 to 300 mb layer is a good area to look for trouble areas. Mid level shear is typically worse as it disrupts the convection well before it can mature.

[deltadog03]

Larry, I usually go by the time of year. Usually in summer I will look at 200mb. However you can look at either one. 200,250 and 300 on the gfs show very light winds over next 36 hours over that area.

[LarryWx]

Thanks Aric and Delta. Time to call it a night. Nobody knows what tomorrow will hold for sure, but it does seem to have suddenly gotten a bit more interesting these last couple of hours not too far away from the SE. What a fascinating system.

IF this were to later affect the SE in a bodily way, I'd lean toward a weak hit on the Carolina's as of now. However, that (strength and track) is far from set in stone. The key is the door is pretty wide open for a potential hit in the SE within a few days if something were to actually get more organized. Also, it appears to me that this system will be moving pretty slowly and may even come close to stalling at times later in the week. So, it may be awhile before we know its ultimate fate.
Good night!

[carolina_73]

Fred sure is a fighter.

[Nimbus]

The convection that is blossoming is quite far east of the LLC. There does still seem to be a closed surface circulation moving west under the new upper level high. The reports we have been getting claim surface pressures have risen and the low pressure at the surface has become very broad and shallow. That would be consistent with a system that spun itself down over a long time.

The exiting trough could be just fanning up convection one last time, and if so ex Fred would dissipate once he gets under the upper level high. Did any of you die hard Fred patrons find any surface pressure readings below 1012? If the LLC had a small area of relatively lower pressure at the surface Fred might have a chance to spin back up. The pro mets are probably correct and the pressure gradient is flat as a pie pan though.

[Aric Dunn]

its never looked this good.. this thing is ridiculous .. lol

[Aric Dunn]

CHeck out the Shear falling like a rock .. right in its path ..lol

[xironman]

CHeck out the Shear falling like a rock .. right in its path ..lol

You can see that just by watching the cirrus. The first set of visibles should be interesting to see where the swirl is compared to the convection.

[deltadog03]

hmmm...just opened the eyeballs for a quick few and what the heck fred. ha the llc still looks pretty solid and its under some nice convection. and if that shear map is correct Aric, this thing could try to spin up today. wxman, I think you need more raid.

[Aric Dunn]

CHeck out the Shear falling like a rock .. right in its path ..lol

You can see that just by watching the cirrus. The first set of visibles should be interesting to see where the swirl is compared to the convection.

its at pretty much 30.3 N 74W heading nearly Due west..

[xironman]

CHeck out the Shear falling like a rock .. right in its path ..lol

You can see that just by watching the cirrus. The first set of visibles should be interesting to see where the swirl is compared to the convection.

its at pretty much 30.3 N 74W heading nearly Due west..

So the convection is displaced east There almost looked like there was a spin a bit south of that earlier on the IR2. Say around 29N, but my eyes hurt from watching this for weeks.

[HURAKAN]

Latest

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT MON SEP 21 2009

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

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

$$
FORECASTER PASCH

[ronjon]

Looks like the LLC has tucked under the western convection near 29.5N-73.5W accoding to shortwave IR SAT - need VIS to confirm. Wow, ole freddie has more lives than a cat. Shear has dropped way down - does it develop or pulse down again. Gonna run smack into a DLM ridge near SC or possibly get pushed SW back toward FL.

http://www.ssd.noaa.gov/goes/east/watl/loop-ir2.html

[alan1961]

http://miami.justweather.com/hurricane/#lightbox=p50

30 minute delay radar on wlpg, loop the GOM.