ATL: FAY - Post-Tropical - Discussion

[GCANE]

Big wave coming into the Carib.
Its going tap into this.

[Aric Dunn]

meso vort number one has already formed right along the coast right near Charleston..

surface obs showing a small circ.

that is the type of thing we will have to watch today. a series of meso vorts spinning up offshore lowering the pressure until one of them finally sticks... as the main circ starts to weaken and broaden out.

[Aric Dunn]

Going to be an interesting day with likely quite a few meso vorts.

one interesting feature is a 925/850mb vorticity heading east passing over the Charleston radar right now. as that approaches the coast and convection builds underneath we will likley see a pretty good meso vort develop.

[GCANE]

Latest soundings, 00Z, showing a good feed of moist GOM air.
Atlanta and Jacksonville humidity measured 85 to 90%.
Charleston measured a 30 knot jet at 250 mb.

[aspen]

ICON still shows a better organized system that moves a little further off of the coast, while the GFS and Euro are slightly stronger compared to previous runs.

[Steve]

Here's a unique webcam to watch the next couple of days. It's the crittervision cam in South Carolina's Low Country. It's color in the daytime and night vision at night. Raccoons and deer mostly feed in the eveninng, and yeah, it's raining there now pretty good. And there are some there now munching in the rain of maybe future Fay.

https://www.youtube.com/watch?v=kLLdLn9Lpok

https://www.youtube.com/watch?v=97KryZmuv5c

This might be the best channel out there! Thanks for exposing us to this masterpiece.

Yeah, it's pretty bomb. I don't watch that many specific channels, but I love crittervision. And since it's in South Carolina close to the coast, I figured it was a good point of reference even though they haven't gotten that much rain at that location. Maybe they'll get some bands in later. I try to check in every couple of days in the evening to watch the deer, raccoons and squirrels feed. Canadian Snow Geese pass by every day, and sometimes, like now, deer are out there getting some morning food. Once in a blue moon they'll have a fox come by or an alligator or whatever, but it's mostly opossums, raccoons, squirrels and deer.

[Aric Dunn]

Second larger meso.vort forming off the SC coast.
This one has some mass with it.

Might see the main circ over GA respond and start moving more east or even ese..

[MGC]

98L still slowly moving eastward in Georgia sampling the peaches. Still a weak surface circulation. Doubt the surface circulation makes it to the beach. 850 vort might intensify over the Atlantic and tour the Mid Atlantic states later this week. 50-50 odds getting named IMO.....MGC

[GCANE]

Mostly clear skies over FL this morning.
Surface heating of the sun is rapidly heating the boundary layer.
Air becoming very unstable with CAPE currently at 4500 and moderately strong lapse rates.
Cumulus starting to build.
Expect a massive blowup in thunderstorms in a few hours.
That should feed a large amount of mid-layer moisture into the system.

[Aric Dunn]

Mostly clear skies over FL this morning.
Surface heating of the sun is rapidly heating the boundary layer.
Air becoming very unstable with CAPE currently at 4500 and moderately strong lapse rates.
Cumulus starting to build.
Expect a massive blowup in thunderstorms in a few hours.
That should feed a large amount of mid-layer moisture into the system.

https://i.imgur.com/wEEBi0T.gif

https://i.imgur.com/xjTVRjl.gif

https://i.imgur.com/3zpJf6R.gif

Yeppers... and this convection will push offshore and lift ne likely creating a larger vorticity which will ultimately take over or pull the circ over ga/sc quickly to the coast.

I am leaning towards a quick reformation this evening offshore sc

[GCANE]

"Feeder-Band" type of convection firing now from Panhandle to MS Delta.
Popups firing up Tampa Bay north to the GA/FL Border.

[tailgater]

Big wave coming into the Carib.
Its going tap into this.

https://i.imgur.com/qu91MX0.png

I was noticing that last night on one of the models showing that wave and associated moisture getting pulled up into 98L, long fetch could be bad news if someone gets stuck under that training affect or it may stay offshore feeding this storm to be.

[tailgater]

Also noticing the radar loop seems to have changed in the last few frames, focus of velocity looks to be more offshore.

[aspen]

On visible satellite imagery, the area of spin is still over east-central Georgia near the border of SC. I’m not sure about the center reforming around the SC coast.

[wxman57]

1014mb low is over eastern Georgia. Pressures along the SC coast are still relatively high, though a trof extends from the inland low to the SC coast. No low forming there (at least currently). I still think it has about a 70-80% chance of becoming at least a depression and quite possibly TS Fay as it passes the DelMarVa Peninsula on Friday. Look for NHC to bump up development chances tonight/tomorrow. I believe that if they to > 60% (high chance) then their SOP says they have to start PTC advisories. Could come as early as tomorrow afternoon. Unless something changes, we'll be initiating advisories tomorrow afternoon.

[aspen]

The GFS, Euro, and CMC don’t move 98L off the coast until Thursday. The ICON, however, gets it over water around midday Wednesday and keeps it over or near the Gulf Stream for 36-48 hours. It’ll probably get over the GS no matter what, but the ICON gets it there quicker and as a better system. However, the CoC would have to reform closer to the convection for that to happen, probably.

[Aric Dunn]

On visible satellite imagery, the area of spin is still over east-central Georgia near the border of SC. I’m not sure about the center reforming around the SC coast.

You need only to look at the surface obs

the flow is shifting to something offshore.

pressure will take time to fall.

1014mb with inland low and 1015mb in and around the meso vorts..

pretty easy to see.

[Aric Dunn]

just the METARS, CMAN and BUOYs. if you add in MESO NET AND CWOP the pictures becomes even clearer.

if you on do the MADIS METAR ( which just rapid metar sites) you can follow things better.

the circ is becoming elongated... being pulled to the convection and higher divergence.

pressure along coast are only 1 MB higher than under the main low. but with convection continuing to increase offshore that probably wont last long...

the process will still take another 12 hours or so. but a reformation is highly likely. Each Meso vort that forms is pulling on the main circ distorting it.

also there is apretty large EDDY/Vort over SE alabama that will swing to the coast over the next several hours. which will likely cause to more eastward tugging of the overall circ.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
Issued by the NWS Weather Prediction Center College Park MD
200 PM EDT Tue Jul 7 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. An area of low pressure located inland over northeastern Georgia
continues to produce a large area of showers and heavy rain over
portions of the southeastern U.S. The low is expected to move
generally northeastward toward the coast of the Carolinas and the
mid-Atlantic states and some development of this system is possible
later this week if it moves over water. Regardless of development,
the low is forecast to produce locally heavy rainfall that could
cause flash flooding across portions of the southeastern U.S. during
the next couple of days.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Zelinsky

[GCANE]

May see a possible Derecho form north of Cocoa Beach.