ATL: INVEST 90L - Discussion

[Stormybajan]

I have it moving inland near Cape Canaveral/Kennedy by early Sunday afternoon with pressure maybe 1010mb. Very weak.

If Wxman has this forming, prepare for CAT 5! I personally still think this will not form btw.

I'm also in that no formation boat with you

[Category5Kaiju]

One thing I do think: if this does manage to form into a tropical system despite the otherwise not so great conditions, I would be quite impressed and believe that the toasty Gulf Stream would have worked its magic once again on these pop up storms.

[captainbarbossa19]

With all the doubting, watch a LLC become better defined underneath convection while/after crossing FL and then become a tropical depression/storm in the Gulf.

[Category5Kaiju]

With all the doubting, watch a LLC become better defined underneath convection while/after crossing FL and then become a tropical depression/storm in the Gulf.

I gotta say, the path that this system is expected to take assuming it does become a TC is extremely strange. Like, what starts off the coast of Georgia and then makes its way south and then west into the Gulf as opposed to simply riding the Gulf Stream on out into the open ocean? That's just unconventional lol

[skillz305]

Had some pretty gnarly downpours and lightning last night (10pm-Midnight) in Vero Beach, FL - from what I assume is Invest 90L!

[Nimbus]

The front is really buckling south and that dry shear would inhibit anything north of the Cape from developing.

[AlphaToOmega]

I would say this is already a tropical cyclone. It has a closed low.

[AlphaToOmega]

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sat Jul 24 2021

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

1. Satellite data indicate that the low pressure system located about
150 miles east of Daytona Beach, Florida, remains elongated and not
well defined. In addition, showers and thunderstorms are currently
limited near the low. However, environmental conditions are
expected to become a little more favorable for development, and a
tropical depression could form during the next day or two while the
low meanders offshore or near the Florida peninsula. Interests in
Florida should monitor the progress of this system.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

Forecaster Cangialosi

[NDG]

I would say this is already a tropical cyclone. It has a closed low.

ASCAT from late last night showed nothing more than a broad & weak circulation, like mentioned by the NHC.
Nothing close to a TD

[NXStumpy_Robothing]

I would say this is already a tropical cyclone. It has a closed low.

The most recent NHC Surface Analysis still has Invest 90L somewhat connected to the front that extends off to its NE. As NDG mentioned, the ASCAT pass that occurred roughly 10 hours ago still showed the circulation to be broad in nature, and more of a surface axis that stretches from the WSW to the NNE. Early-morning visible imagery does show a decently-defined circulation in the lower-level clouds, but it's entirely possible that it's not closed/circular, and it's still attached to that front as previously mentioned.

Regardless, we should hopefully have recon flying out this afternoon to investigate the area, so we should have more concrete answers on the current status of 90L then. We should also hopefully have another round of ASCAT passes before that flight takes off.

[NDG]

Mostly still a weak naked large broad swirl this morning.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sat Jul 24 2021

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

Showers and thunderstorm activity has increased a bit this morning
in association with the low pressure system located about 200 miles
east of Daytona Beach, Florida. Nearby buoy observations also
indicate that surface pressures have been falling close to the
center of this system. However, the associated shower and
thunderstorm activity remains disorganized and located primarily
south and east of the center. Environmental conditions are
forecasted to become a bit more favorable for development, and a
tropical depression could form over the next day or so while the low
meanders offshore of the Florida Peninsula. Interests in Florida
should continue to monitor the progress of this system. An Air
Force Reserve Hurricane Hunter aircraft is scheduled to investigate
the system later today, if necessary.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

$$
Forecaster Papin/Beven

[abajan]

Somehow the Storm2K map still hasn't updated to show 90L as yet. Hmm

[AlphaToOmega]

Chances are higher than 60%. If the chances go to 70% of higher, I say guaranteed development. No "red" AOI has failed to develop this year.

[boca]

We are under a flood watch down here in South Florida from this low pressure area 2 to 4 inches thru Monday with possible higher amounts possible.

[wxman57]

I doubt it will look any more impressive tomorrow when the center moves into Florida. Take a look at the 400-700mb RH on Levi's site. Florida is "brown". Lots of dry air. Euro and GFS indicate less than 1/2" of rain where it moves inland. Highest rain is Miami area 1-3 inches. No wind, little rain, but the NHC appears like they want to get at least a depression out of it. It may be a stretch calling it a depression at any point before it reaches Florida, but requirements have declined over the decades.

[wxman57]

Chances are higher than 60%. If the chances go to 70% of higher, I say guaranteed development. No "red" AOI has failed to develop this year.

It's not a question of whether or not it will "develop". That was never in doubt. The question has always been whether the NHC would call the low a depression.

[AlphaToOmega]

Invest 90L
As of 06:00 UTC Jul 24, 2021:

Location: 29.3°N 78.5°W
Maximum Winds: 25 kt Gusts: nan kt
Minimum Central Pressure: 1015 mb
Environmental Pressure: 1017 mb
Radius of Circulation: 150 nm
Radius of Maximum Wind: 100 nm

[Weatherboy1]

Looks to be tightening up a little bit this morning … but without some convection firing and holding over the center, not going to get much out of this IMO

[AlphaToOmega]

Invest 90L
As of 12:00 UTC Jul 24, 2021:

Location: 29.2°N 77.4°W
Maximum Winds: 25 kt Gusts: nan kt
Minimum Central Pressure: 1013 mb
Environmental Pressure: 1017 mb
Radius of Circulation: 150 nm
Radius of Maximum Wind: 100 nm