Invest 92L--50% two day, 90% five day odds

[WxWatcher007]

The Atlantic has been exceptionally quiet for a second consecutive September, but it looks as if the basin is trying to wake back up with a robust tropical wave heading through the tropical Atlantic. 

The wave, focused near 30W, is most likely still a few days away from consolidating and kicking off the process of tropical genesis, but with a strong model signal from operational/ensemble/AI models, and the wave producing much more convection than the failed development of 91L, this one looks like it will become a TC eventually. 

There are still some headwinds, figuratively and literally. In the image above you can see stable air to the northwest of the wave. Further west, there is wind shear evident with what little convection being blown over. Long term though, once this wave is able to consolidate, it will have a chance to intensify. 

Long way away from that however. 

[GaWx]

12Z runs regarding this MDR AOI:

-GFS/CMC/Icon all have this eventually as a H with GFS/CMC both recurving well E of Bermuda (Icon doesn’t go out far enough to tell)

-JMA has this as a TD at 48 and a TS at 72. This is stronger than the two prior 12Z runs that each had it as only a TD.

-Euro has a MH passing just SE of Bermuda

-UKMET again has this as a TS. This is a bit further W than recent runs but it’s still aiming a bit E of Bermuda as of 168:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS
FORECAST POSITION AT T+ 72 : 16.4N 47.4W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 17.09.2025 72 16.4N 47.4W 1006 40
0000UTC 18.09.2025 84 17.7N 48.8W 1006 42
1200UTC 18.09.2025 96 19.5N 52.1W 1006 44
0000UTC 19.09.2025 108 20.6N 54.3W 1006 40
1200UTC 19.09.2025 120 22.8N 55.1W 1006 44
0000UTC 20.09.2025 132 23.1N 57.0W 1005 43
1200UTC 20.09.2025 144 25.1N 57.7W 1003 46
0000UTC 21.09.2025 156 26.3N 58.6W 1001 49
1200UTC 21.09.2025 168 28.3N 59.3W 999 48

[GaWx]

0Z runs

-are fairly similar to the 12Z for the Icon, GFS, and CMC

-This time the UKMET is even further W and threatens Bermuda:

0Z UK: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS
FORECAST POSITION AT T+ 72 : 18.0N 48.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 18.09.2025 72 18.0N 48.8W 1008 38
1200UTC 18.09.2025 84 20.0N 51.3W 1007 42
0000UTC 19.09.2025 96 21.2N 53.2W 1007 38
1200UTC 19.09.2025 108 22.7N 55.1W 1008 30
0000UTC 20.09.2025 120 22.5N 57.2W 1008 32
1200UTC 20.09.2025 132 23.1N 58.3W 1009 31
0000UTC 21.09.2025 144 23.3N 59.8W 1008 33
1200UTC 21.09.2025 156 23.9N 61.0W 1008 35
0000UTC 22.09.2025 168 24.3N 63.1W 1007 31

[GaWx]

12Z runs:

-GFS/CMC favoring an H but well E of Bermuda

-Euro is very close to but just NE of Bermuda with an H

-Icon is well to the SW of those other 3 and it’s fate is still unknown at 180 with it a TS S of Bermuda just starting a NW recurve

-12Z JMA out to 72 so far: TC moving NW way out there

-12Z UKMET like prior run threatens Bermuda with this run aimed only a little E of there:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS
FORECAST POSITION AT T+ 54 : 17.5N 46.9W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 18.09.2025 60 18.3N 47.8W 1007 41
1200UTC 18.09.2025 72 20.5N 50.5W 1007 43
0000UTC 19.09.2025 84 21.3N 53.4W 1007 41
1200UTC 19.09.2025 96 22.5N 55.5W 1007 31
0000UTC 20.09.2025 108 23.3N 57.0W 1007 32
1200UTC 20.09.2025 120 25.2N 58.1W 1007 38
0000UTC 21.09.2025 132 26.6N 58.4W 1004 44
1200UTC 21.09.2025 144 27.7N 60.4W 1002 41
0000UTC 22.09.2025 156 29.0N 61.7W 999 49
1200UTC 22.09.2025 168 30.6N 62.4W 995 51

[GaWx]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
Issued by the NWS Weather Prediction Center College Park MD
200 PM EDT Mon Sep 15 2025

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

Central Tropical Atlantic (AL92):
A broad area of low pressure has formed roughly midway between the
Windward Islands and the coast of west Africa. This system has
become better organized since yesterday and is expected to move
through a favorable environment for further development. A
tropical depression or tropical storm is likely to form by the
middle to latter part of this week as the system moves
west-northwestward at 10 to 15 mph over the central tropical
Atlantic.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Blake/Putnam

[WxWatcher007]

Models are quite robust once 92L gets north of the islands.

[GaWx]

 12Z JMA completed (fwiw): Although the 72 hour map had it recurving NW seemingly way out in safe recurve land, it then turned W through 144 getting it to 21N, 62W (similar to Icon). Then it does a recurve WNW and then NW ending at 25N, 70W.