ATL: FRED - Post-Tropical - Discussion

[SFLcane]

Tropical Cyclone Formation Alert posted

[url]https://i.postimg.cc/nVdQSjyz/al942021-21080906.gif [/url]

So, it’s imminent TD soon right?

Not guaranteed this is just a marine graphic.

[wxman57]

I don't see clear evidence of an LLC. Scatterometer pass indicated an elongated circulation. Visible loop inconclusive. I have a TD moving up west coast of FL this weekend. Could be classified as a TS south of PR tomorrow afternoon/evening, followed by weakening. Better chance it passes west of FL than east of FL. Still, models indicate it will be struggling and weak.

[alienstorm]

If there is an LLC it is NNE of Barbados

https://www.weathernerds.org/satellite/?initsatsrc=On&initsatname=GOES16&initsattype=vis&initcscheme=vis1&initimdimx=1050&initimdimy=764&initrange=17.500:-64.750:9.000:-50.750&initloop=True&initnframes=20&initlightning16=On&initlightning17=Off&initltngfed=Off&initltngtoe=Off&initinterstates=On&initwarnings=On&initlatlon=On&initascata=Off&initascatb=Off&initascatc=Off&initascatamba=Off&initascatambb=Off&initascatambc=Off&initsst=Off

[AtlanticWind]

I think most likely this gets pretty ripped up over the Islands.
But as I said yesterday I still think this has a chance to get
North of the islands with either a couple of reformations to the northeast
or a suprising temporary movement to the north kinda like Dorian did.

If it clears the islands to the north I think it could make a run at a stronger T.S.

[AlphaToOmega]

There is some obvious banding with this system, and we are nearing diurnal minimum.

[wxman57]

Winds still NE at 15 kts in Barbados. I would expect to see NW winds there if the circulation was closed.

[wx98]

I was behind and just read all the posts from yesterday about midday. Very interesting to see the growing consensus of people believing it would go south of Barbados and miss Hispaniola which has now switched to north of Barbados and right toward the shredder.

[Category5Kaiju]

We just need PTC designation, just to make sure the islands are prepared for squally conditions

[AlphaToOmega]

The GFS and CMC show a gulf landfall for Invest 94L. If you live near the Gulf coast, do not search up the upper ocean heat content in the Gulf of Mexico

[Hammy]

Still not closed but 13N 58.5W is about where the low is trying to consolidate.

[USVIKimmie]

The 2pm is out

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Aug 9 2021

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

1. Showers and thunderstorms associated with the area of low pressure
located about 100 miles east-northeast of Barbados continue to show
signs of organization. However, recent satellite wind data indicates
that the system currently lacks a well-defined center.
Environmental conditions are expected to remain conducive for
additional development, and a tropical depression is likely to form
later today or tonight while the low moves west-northwestward at 10
to 15 mph. The disturbance is forecast to move through portions of
the Lesser Antilles tonight, then move near the Virgin Islands and
Puerto Rico on Tuesday, and Hispaniola on Wednesday. Tropical storm
watches or warnings could be required this afternoon with
shorter-than-normal lead times for portions of the Lesser Antilles,
the Virgin Islands, and Puerto Rico. In addition, heavy rains and
flooding are likely for the Leeward Islands, Virgin Islands, and
Puerto Rico. Interests in those areas should monitor the progress
of this system.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

2. Showers and thunderstorms in association with an elongated low
pressure area located several hundred miles east of the Lesser
Antilles have diminished. Environmental conditions have become
unfavorable and development of this system is no longer expected.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...near 0 percent.

Forecaster Brown/Papin

[tolakram]

Floater RGB view
https://www.star.nesdis.noaa.gov/GOES/meso_band.php?sat=G16&lat=13N&lon=57W&band=DayLandCloud&length=210

[SouthDadeFish]

94L is steadily organizing today, which is impressive to me considering the diurnal cycle. I see improved convective banding too. The fact that the deepest convection is to the northeast of the trough axis raises the question of whether the center may get tugged up that way. I'd keep an eye on to see how convection persists. I'm thinking we probably see another big blow-up of convection this evening/overnight, which allows the system to become a legit TC. Either way, I would think this system warrants PTC advisories.

[SouthDadeFish]

Winds still NE at 15 kts in Barbados. I would expect to see NW winds there if the circulation was closed.

To play devil's advocate, a closed center could exist ~200 km NE of Barbados and may not be large enough to be reflected by the surface obs in Barbados. However, you are likely correct that the circulation is not quite closed yet. I think it's close though.

[psyclone]

Definitely looks like relentless, even if lurchy, development is underway. the tropics can surprise us all. after the flop of 92L, 94L is outperforming thus far.

[AlphaToOmega]

Showers and thunderstorms associated with the area of low pressure
located about 100 miles east-northeast of Barbados continue to show
signs of organization. However, recent satellite wind data indicates
that the system currently lacks a well-defined center.
Environmental conditions are expected to remain conducive for
additional development, and a tropical depression is likely to form
later today or tonight while the low moves west-northwestward at 10
to 15 mph. The disturbance is forecast to move through portions of
the Lesser Antilles tonight, then move near the Virgin Islands and
Puerto Rico on Tuesday, and Hispaniola on Wednesday. Tropical storm
watches or warnings could be required this afternoon with
shorter-than-normal lead times for portions of the Lesser Antilles,
the Virgin Islands, and Puerto Rico. In addition, heavy rains and
flooding are likely for the Leeward Islands, Virgin Islands, and
Puerto Rico. Interests in those areas should monitor the progress
of this system.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

[AtlanticWind]

I was behind and just read all the posts from yesterday about midday. Very interesting to see the growing consensus of people believing it would go south of Barbados and miss Hispaniola which has now switched to north of Barbados and right toward the shredder.

i

It was a little perplexing last night with a lot of posters saying it was going south
Of the islands with all the models heading for Puerto Rico.
I still think this could slip just north of the Greater Antilles and
possibly be a little bigger problem downstream.

[Stormybajan]

I was behind and just read all the posts from yesterday about midday. Very interesting to see the growing consensus of people believing it would go south of Barbados and miss Hispaniola which has now switched to north of Barbados and right toward the shredder.

i

It was a little perplexing last night with a lot of posters saying it was going south
Of the islands with all the models heading for Puerto Rico.
I still think this could slip just north of the Greater Antilles and
possibly be a little bigger problem downstream.

For a time there yesterday I was thinking somewhere between St.Lucia and Martinque because all of the convection was basically south of Barbados at the time, despite what models were saying. As we know now after that the convection keep drying up and pulsing up more to the NE eachtime and now 94L is back on track exactly where the models said it would be. #NeverDoubtTheModels.....meanwhile its starting to get that look of a organizing tropical depression

[cycloneye]

TXNT21 KNES 091750
TCSNTL

A. TROPICAL DISTURBANCE (94L)

B. 09/1730Z

C. 13.5N

D. 58.6W

E. THREE/GOES-E

F. T1.5/1.5

G. IR/EIR/VIS

H. REMARKS...3/10 BANDING AROUND LLCC YIELDS DT OF 1.5. MET AND PT
AGREE AND FT IS BASED ON MET DUE TO BANDING NOT BEING CLEAR-CUT.

I. ADDL POSITIONS

NIL


...MLEVINE

[NXStumpy_Robothing]

Given the wording in the various Tropical Weather Outlooks that have been issued over the past day or so, I'm a bit surprised to see that the NHC did not opt to make use of the PTC designation today. Most model guidance shows some amount of strengthening and consolidation tonight, and has done so for a few runs - given the current strength of the system and today's trends, that would likely merit TS warnings over parts of the Lesser Antilles.

As for 94L itself, the system appears to be attempting to pinch off the northern edge of its surface trough a bit ENE of Barbados. We should see the system move WNW or even NW for a bit before switching to a more westward motion as it approaches (or goes over) the Greater Antilles. Like Elsa, it appears that the ultimate fate of this storm (for us in the States, at least) is going to come down to whether it can shrug off/avoid the worst terrain interaction, and the amount of strength it can manage to acquire over the Eastern Caribbean before then. Small systems like this can spin up and down quite quickly.