ATL: Ex INVEST 91L - Discussion (0/0)

[cycloneye]

 https://x.com/NHC_TAFB/status/1963685306135166998

[cycloneye]

18z Best Track:

AL, 91, 2025090418, , BEST, 0, 121N, 342W, 20, 1011, DB

[Hurrilurker]

That NHC "development cone" keeps steadily ticking more and more south on the west end.

[SconnieCane]

Oh *bleep,* that new red shaded zone of potential formation (not yet really a "cone" based on track forecast points, remember) is a lot further southwest and now encompasses portions of the northern, central AND southern Lesser Antilles.

Operational global runs are well-nigh useless for intensity at this range. There might be a TUTT that imparts detrimental shear on it, there might not.

[cycloneye]

 https://x.com/zoom_earth/status/1963708725455450565

[Blown Away]

18z Best Track:

AL, 91, 2025090418, , BEST, 0, 121N, 342W, 20, 1011, DB

91L may be consolidating a bit north of 12.1N/34.2W?

[mpic]

What time frame are we looking at IF it comes into the Gulf? Trying to make plans for a surgery.

[ouragans]

What time frame are we looking at IF it comes into the Gulf? Trying to make plans for a surgery.

More than 14 days

[cycloneye]

Josh is watching very closely.

 https://x.com/iCyclone/status/1963728816599105602

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Thu Sep 4 2025

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

Tropical Atlantic (AL91):
A broad area of low pressure, associated with a tropical wave, is
producing a concentrated but still disorganized area of showers and
thunderstorms over the eastern tropical Atlantic. Environmental
conditions are favorable for development of this system, and a
tropical depression is likely to form by this weekend as it moves
slowly westward at 5 to 10 mph across the central tropical Atlantic.
This system is likely to be near the Lesser Antilles by the middle
to latter part of next week, and interests there should continue to
monitor its progress.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Berg

[chaser1]

Someone wake up Wxman or any of the other dozen or so Pro Mets here LOL. Peak week of the season with a 60/90 MDR Invest, along with models that are throwing a grab-bag of intensity & track solutions. Yet, mum's the word from any of them (or Levi for that matter)??

[hipshot]

Someone wake up Wxman or any of the other dozen or so Pro Mets here LOL. Peak week of the season with a 60/90 MDR Invest, along with models that are throwing a grab-bag of intensity & track solutions. Yet, mum's the word from any of them (or Levi for that matter)??

I've been checking Levi's website and nothing yet but he was probably waiting for it to be declared an invest so he should have something to say soon.

[BobHarlem]

18z best track was 12.1N but this looks more like 13.5N. Probably another round of model changes overnight.

[Deshaunrob17]

I’m not surprised one bit that Euro has it weak. Models won’t handle this system properly.
1. Lots of dry air keeping it small- reminds me of how Dorian started .
2. A wave still embedded within the monsoon mess.

I won’t trust models as yet. Also, never trust these small system during the peak of season.

[cycloneye]

More south.

AL, 91, 2025090500, , BEST, 0, 117N, 346W, 20, 1011, DB

[hipshot]

More south.

AL, 91, 2025090500, , BEST, 0, 117N, 346W, 20, 1011, DB

https://i.imgur.com/VW0f3rB.png

This is starting to look a little spooky!!

[chaser1]

More south.

AL, 91, 2025090500, , BEST, 0, 117N, 346W, 20, 1011, DB

https://i.imgur.com/VW0f3rB.png

Ummm, I must be living in some alternate Universe then. There is not any convection at those coordinates but there sure appears to be some random CDO exhibiting rotation and banding between 2-3 degrees north of there. So NHC believes that a potential MLC is going to relocate approx 100 miles to the SSW in alignment with the broader LLC? I seriously would like to understand their thinking.

[Teban54]

18z best track was 12.1N but this looks more like 13.5N. Probably another round of model changes overnight.

https://i.postimg.cc/Qd5ZGcWp/48741101.gif

91L's mid-level vorticity is well to the north of low-level now, so it could simply be that what we're seeing from satellite at 13-14N isn't making it down to the surface.

If upcoming convective bursts tonight continue to focus around 14N, I wouldn't be surprised if it consolidates further north. That said, the hurricane models seem to suggest that convection will spread from 11N to 14N tonight.

850-700-500 mb vorticity:

[Teban54]

91L is also at a boundary with high shear to the north and low shear to the south, possibly explaining the discrepancy:

[chaser1]

Albeit slowly, 91L appears to already be moving west of any near term upper level shear (whether it be at 11.5 N or 14.0 N). Point being, the MLC is dominant and it's 2 degrees north of Best Track. My eyes are having a hard time unseeing that.