Low Pressure in the Northwest Caribbean Sea (Is Invest 93L)

[NDG]

Very evident surface vorticity on vis sat this morning, but fairly broad at this time.

[Kingarabian]

06z Euro through 90 hrs, almost identical to its earlier 0z run.

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

Looked a little slower vs the 12z.

[toad strangler]

Florida on Alert for Increasing Tropical Threat Next Week
Tropical system expected to form over Gulf waters and head toward Florida for early next week
MICHAEL LOWRY
AUG 25

A broad area of spin and storminess pivoting across Central America into the northwestern Caribbean today is forecast to slowly come together by this weekend near the Yucatán Channel and emerge over the eastern Gulf of Mexico early next week. The National Hurricane Center expects a tropical depression or storm to form in the coming days and move toward Florida from next Tuesday to Thursday.

While for now models don’t show a strong system approaching Florida, the unique setup in late August is one that could allow the system to overachieve and quickly strengthen more than currently advertised. Given the forecast potential, Floridians are encouraged to check back throughout the weekend for the latest information.

What to expect this weekend

The biggest short-term factor with the low-pressure area is how much entanglement with land disrupts early development. If the fledgling circulation tries to take shape over land – specifically Mexico’s Yucatán Peninsula – it will be a speed bump to formation this weekend. Models have been vacillating on exactly where the spin may try to consolidate, so our focus this weekend will be where and how quickly the system organizes. The current model consensus is for slower development over the weekend due to proximity to land.

Where it’s headed next week

Forecast models are in good agreement on the steering pattern for next week. A dip in the jet stream ushering in a cold front to the southeastern U.S. will pick up the system and steer it northeastward beginning on Monday and slingshotting it toward Florida’s Gulf coast by Tuesday through Wednesday. Of course, for a state like Florida with a slanted coastline, the fine details matter and as we’ve seen in recent years a slight deviation in approach angle can translate into a big difference in where a storm system comes ashore.

Low-pressure tracks from the overnight run of the European ensemble forecast system. A greater number of weak low-pressure tracks (shown in blue) are farther south, with stronger scenarios farther north. Credit: Weathernerds.org
Given the orientation of upper-level winds, a broader, weaker system would favor an approach farther south over the Florida peninsula. A more organized storm would lean farther north toward Florida’s Big Bend or eastern panhandle. In either case, the surge of tropical air and storminess will tilt largely east of the low pressure circulation, which means much of Florida will be affected by wet and unsettled weather through mid-week.

How strong will it get?
As we discussed in Thursday’s newsletter, an upper-level low sliding west of the system on Monday into Tuesday will orient upper-level winds in a manner that could promote strengthening – perhaps quickly – as the system accelerates northeastward, but it depends on the exact strength and positioning of the upper-level low, which remains in question. For now, guidance suggests a tropical depression or tropical storm threat to Florida next week, but those on Florida’s west coast should be aware of the potential for strengthening on approach.

The bottom line
Areas of west-central Florida could use the rainfall, so a weaker system wouldn’t be entirely unwelcome news. However, given the time of year and upper-level setup, those from southwest Florida to the panhandle should monitor the forecasts this weekend as the potential exists for a strengthening storm system on approach next week. Even low-grade tropical storms can create coastal flooding issues along Florida’s west coast. South Florida can expect a stormy, unsettled pattern through mid-week regardless of development.

© 2023 Michael Lowry
3401 West Hallandale Beach Boulevard, Pembroke Park, Florida 33023

[Stormcenter]

Nothing much there now, maybe the GFS
has been right all along in reference to this not amounting
to much overall. We shall see.

[chris_fit]

Nothing much there now, maybe the GFS
has been right all along in reference to this not amounting
to much overall. We shall see.

The GFS is now developing this. All models are onboard.

[Ianswfl]

Very evident surface vorticity on vis sat this morning, but fairly broad at this time.

https://i.imgur.com/1U3AsCU.gif

Also further north and to the east than many of the models. Might speed things up faster for earlier impact and further south too.

[SFLcane]

oops!

 https://twitter.com/TylerJStanfield/status/1695063529038942644

[SFLcane]

Very evident surface vorticity on vis sat this morning, but fairly broad at this time.

https://i.imgur.com/1U3AsCU.gif

Lonnng way from being classified thats for sure.

[wxman57]

No TD until maybe Monday. North of Tampa sunrise Wed. 55kts.

[chaser1]

GFS 06Z appearing to finally lean into a deeper low then prior runs showing only a stretched-out trough crossing Florida. This not only appears in line with nearly all global models (even the hapless NOGAPS), but even as depicted by regional RGEM mesoscale. With potential Panama City to Tampa landfall projected no earlier than 0Z Wed., I'd guess that NHC would not see a reason for considering PTS advisories any earlier then Sunday evening. At the same time, NHC will likely increase the drumbeat by later today to increase awareness given how most people tend to detach from the news a bit over the weekend. I'd guess we'll see chances of development of 30/90 by this evening along with stronger language for Florida W. Coast and E. Panhandle for coastal interests as well as heavy rainfall/localized flooding risk that may threaten by mid-week. Reality is, nothing is going to develop super-fast and i'd guess that a high-end TS will impact around Cedar Key around late Wednesday.

[CronkPSU]

Very evident surface vorticity on vis sat this morning, but fairly broad at this time.

https://i.imgur.com/1U3AsCU.gif

Lonnng way from being classified thats for sure.

depends on your definition of lonnnng....NHC odds imply they think it will within 5 days

[psyclone]

We're at the time of the year where the climo tailwind kicks in. 50kt slop storm ts to cedar key remains my non professional guess. West Central FL needs the rain desperately so this would put them in a good spot for needed rains.

[SFLcane]

No TD until maybe Monday. North of Tampa sunrise Wed. 55kts.

2023 the year of the tropical storms.

[USTropics]

4 run trend of the ECMWF ensembles:


GFS ensembles:

[Spacecoast]

No TD until maybe Monday. North of Tampa sunrise Wed. 55kts.

Is this 55kts, @ 10m? Weathernerds (above) shows ~35-45knts.

[Teban54]

I know people are naturally more concerned about the FL landfall, but depending on track, the system may achieve its peak intensity in the subtropical Atlantic once it emerges back over water. Euro has been showing this consistently, and there are also some hints on the CMC (though it doesn't always keep the system as a TC). Can add a bit more ACE if this verifies.

Land impacts beyond FL can't be ruled out, either. Euro is currently showing a Fiona-like scenario where the system takes a sudden left turn towards Nova Scotia and Newfoundland. CMC shows it affecting the same regions as an extratropical cyclone.

[MississippiWx]

4 run trend of the ECMWF ensembles:
https://i.postimg.cc/1zPdgSYq/gifmaker-me-12.gif

GFS ensembles:
https://i.postimg.cc/NF7Dv2BC/gifmaker-me-13.gif

Selfishly (and likely unrealistic), I would love to see the westward shift continue in that Euro Ensemble. I've lost track of our consecutive 100+ degree days here in South MS and we have gone over a month now with no rain. This has never happened in my lifetime. My slim hope is models struggle to figure out where to consolidate the low and it winds up in the Central Gulf. Not gonna happen, though. Enjoy the rain and cooler weather, Florida. Just know that Texas, Louisiana, and Mississippi residents are highly envious.

[Hypercane_Kyle]

You know what? I think I'm going to go bold on this one:

75 knot Cat 1 north of Cedar Key. This storm reminds me a lot of 1998's Hurricane Earl. Likely a one sided storm, highly sheared, but aligned just enough to where that sheer will provide some ventilation.

[Blown Away]

IMO any delays in Franklin moving N will cause this AOI to move farther W once in the EGOM.

[cycloneye]

IMO any delays in Franklin moving N will cause this AOI to move farther W once in the EGOM.

Franklin is moving ESE now.