ATL: INVEST 93L - Discussion

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Jul 14 2025

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

East of the Florida Peninsula into the Northeastern Gulf (AL93):
An area of low pressure located offshore of the east coast of
Florida continues to produce disorganized showers and thunderstorms
primarily south of the center. This system is forecast to move
westward across the Florida Peninsula on Tuesday and Tuesday night,
eventually moving into the northeastern Gulf by the middle part of
this week. Environmental conditions appear generally favorable for
additional development if the system remains offshore, and a
tropical depression could form as the system moves across the
northeastern and north-central Gulf by the middle to latter part of
this week.

Regardless of development, heavy rainfall could produce localized
flash flooding over portions of Florida and the north-central Gulf
coast through the middle to latter portion of this week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...medium...40 percent.

$$
Forecaster Papin

[TomballEd]

Outflow boundary W of 93L is not something you want to see if development will be quick. 18Z GFS and ensembles still not excited. Will be interested to see how this looks crossing Florida.

[Nimbus]

There were 4+ inches an hour rain rates in that first band that crossed Florida.
Ship reporting low surface pressure near 28N, 80W if a new center blows up south of 28N the models will have to be initialized differently anyways. The dry air just to the north and proximity to land will hopefully keep this as just an invest for a while.

[Category5Kaiju]

Looks like the deep-layer shear over 93L has really dropped since earlier....

[HurricaneBelle]

There were 4+ inches an hour rain rates in that first band that crossed Florida.
Ship reporting low surface pressure near 28N, 80W if a new center blows up south of 28N the models will have to be initialized differently anyways. The dry air just to the north and proximity to land will hopefully keep this as just an invest for a while.

Areas near Plant City, east of Tampa, received 10+ inches of rain today.

[cycloneye]

00z Best Track: Begins the turning to the west.

AL, 93, 2025071500, , BEST, 0, 289N, 791W, 25, 1014, DB

[LarryWx]

The "Shrimp" look is something I've seen in strengthening tropical systems before, but not sure how much of it is legit or just part of the nighttime storm cycle. If it's legit, may as well make the 8pm TWO 80-90%.
https://i.postimg.cc/nrPrY4bY/goes19-ir-nwatl.gif

I’m not sure it’s really a shrimp look. I think a convergence zone setup inland between the sea breeze from the west and the flow around 93L from the east. This area will likely die out once the sun goes down. In fact, the majority of the convection over water is weakening as we hit diurnal minimum over water.

Hard to say what is going on underneath the hood without ASCAT/recon. Just from visible, it appears the surface low/vort is moving off the west and the mid level area is dropping southwest a bit. If this continues, the globals will be correct. Long way to go for this to be a TC…in my opinion.

Indeed, the seabreeze, helped by the general onshore flow north of 93L, strongly pinned afternoon thunderstorms further inland in this area in a long band near and just west of I-95. That’s what Andy is referring to. It’s not a direct part of 93L, itself. It’s just typical diurnal summertime convection being driven by the cooler seabreeze running into the hotter, very moist/unstable air just inland.

[cycloneye]

There is a jump on the loop and is because of the new 00z best track position.

[cycloneye]

[cycloneye]

 https://x.com/AndyHazelton/status/1944940819783307682

[TomballEd]

Acadiana?

 https://x.com/robperillo/status/1944934629078700105

[weeniepatrol]

40/40, huh?

[chaser1]

This thing looks like it's in a hurry to develop. Visually, Satellite & radar suggest an aligning LLC & MLC. ASCAT suggesting the same. 93L may be one of those oddball systems that'll continue to organize even as it crosses over the state. I'd say Melbourne may be in line for a solid tropical dumping come daybreak.

[kevin]

Two ships measured 10-minute averaged wind speeds at the surface of 50 kmh (3 hours ago) and 44 kmh (7 hours ago) near the center of 93L. Translated to knot and using a 1.14 conversion factor results in 1-minute wind speeds of 31 kt and 24 kt, respectively. Another ship in the same region (without wind data) has a latest hourly pressure reading (41 minutes ago) of 1012.6 mb north of 93L and still dropping. Furthermore, the latest ASCAT pass from 7 hours ago shows decent organization and is in-line with the ship measurements since ASCAT also shows one barb near 25 kt. I think that if there was a plane in 93L right now it'd be upgraded to a 30 kt TD. Since that won't happen, I won't be surprised if we immediately go from 93L to a PTC or TS Dexter once this gets named.

[Nimbus]

Surface winds out of the north at St Augustine with pressures dropping there.
Should see the wind shift to out of the east there before the ASCAT core landfalls.
Peak winds of 25 knots it won't be taking out the power lines.

[weeniepatrol]

Two ships measured 10-minute averaged wind speeds at the surface of 50 kmh (3 hours ago) and 44 kmh (7 hours ago) near the center of 93L. Translated to knot and using a 1.14 conversion factor results in 1-minute wind speeds of 31 kt and 24 kt, respectively. Another ship in the same region (without wind data) has a latest hourly pressure reading (41 minutes ago) of 1012.6 mb north of 93L and still dropping. Furthermore, the latest ASCAT pass from 7 hours ago shows decent organization and is in-line with the ship measurements since ASCAT also shows one barb near 25 kt. I think that if there was a plane in 93L right now it'd be upgraded to a 30 kt TD. Since that won't happen, I won't be surprised if we immediately go from 93L to a PTC or TS Dexter once this gets named.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Tue Jul 15 2025

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

1. East of the Florida Peninsula into the Northeastern Gulf (AL93):
Recent satellite-derived wind data indicate that the area of low
pressure located just offshore of the east coast of Florida is
gradually becoming better defined. However, the shower and
thunderstorm activity remains disorganized. This system is forecast
to move westward across the Florida Peninsula today and tonight,
then reach the northeastern Gulf by the middle part of this week.
Environmental conditions appear generally favorable for additional
development, and a tropical depression could form by the middle to
latter part of this week as the system moves across the northeastern
and north-central Gulf.

Regardless of development, heavy rainfall could produce localized
flash flooding over portions of Florida through mid-week. Heavy
rainfall could also cause flash flooding for portions of the
north-central Gulf Coast during the middle to latter portions of
this week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...40 percent.



Forecaster Hagen

[cycloneye]

From two hours ago.

[cycloneye]

 https://x.com/webberweather/status/1945041932796805379

[weeniepatrol]