Invest 92L--90% 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.

[GaWx]

Now 60/90: is the long drought about to be broken? Keep in mind though that 91L also made it to 60/90 along with strong model support and surprisingly never developed:

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Sep 15 2025

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

1. Central Tropical Atlantic (AL92):
A broad area of low pressure is located about midway between
the Windward Islands and the coast of west Africa. This system
is showing signs of organization, 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 while the system moves west-northwestward
at 10 to 15 mph over the central tropical Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...90 percent.



Forecaster Pasch

 

[WxWatcher007]

1 minute ago, GaWx said:

Now 60/90: is the long drought about to be broken? Keep in mind though that 91L also made it to 60/90 along with strong model support and surprisingly never developed:

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Sep 15 2025

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

1. Central Tropical Atlantic (AL92):
A broad area of low pressure is located about midway between
the Windward Islands and the coast of west Africa. This system
is showing signs of organization, 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 while the system moves west-northwestward
at 10 to 15 mph over the central tropical Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...90 percent.



Forecaster Pasch

 

Yeah that's in the back of my mind, but I think the distinction here is the much larger moisture envelope and ability of this one to keep up convection. Environment looks pretty favorable for development/intensification in the subtropics too, which worked well with Fernand. 

[Wannabehippie]

1 hour ago, GaWx said:

Now 60/90: is the long drought about to be broken? Keep in mind though that 91L also made it to 60/90 along with strong model support and surprisingly never developed:

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Sep 15 2025

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

1. Central Tropical Atlantic (AL92):
A broad area of low pressure is located about midway between
the Windward Islands and the coast of west Africa. This system
is showing signs of organization, 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 while the system moves west-northwestward
at 10 to 15 mph over the central tropical Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...90 percent.



Forecaster Pasch

 

There was more SAL when 91L was around. That has cleared out an area, where 92L is at right now. There is still some ahead of it, and a big blob behind it. But where it is right now it is in a good spot. 92L also has a lot more convection than 91L ever had associated with it. 92L still will need to have that dry air ahead of it get out of the way, or it will fizzle out as well IMHO. No closed circulation that I can pick out with my untrained eyes.

 

blob:https://www.tropicaltidbits.com/75019b3b-06c8-416d-8b72-d0c8bb3da341

 

[Coach McGuirk]

It's a fish storm. 

[GaWx]

1 hour ago, Coach McGuirk said:

It's a fish storm. 

Many are. And at least there’d be something interesting to follow with hopefully nobody needing to worry about potential devastation and casualties. I say hopefully nobody because there’s still some chance Bermuda will be hit. Fortunately though, Bermuda handles storms pretty well due to good elevation just off many of the beaches (hilly terrain) and very strict building codes. This includes limestone roofs! I’ve been there.

[GaWx]

8AM TWO: getting very close now…

Central Tropical Atlantic (AL92):
Showers and thunderstorms associated with a broad low pressure area
located about midway between the Windward Islands and the coast of
west Africa have become better organized since yesterday.
Environmental conditions are conducive for additional development,
and a tropical depression or storm is likely to form in the next day
or two as the system moves west-northwestward or northwestward at 10
to 15 mph over the central tropical Atlantic.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Wannabehippie]

5 minutes ago, GaWx said:

8AM TWO: getting very close now…

Central Tropical Atlantic (AL92):
Showers and thunderstorms associated with a broad low pressure area
located about midway between the Windward Islands and the coast of
west Africa have become better organized since yesterday.
Environmental conditions are conducive for additional development,
and a tropical depression or storm is likely to form in the next day
or two as the system moves west-northwestward or northwestward at 10
to 15 mph over the central tropical Atlantic.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

Satellite photos show an ULL dropping down, that probably will interfere with development.


blob:https://www.tropicaltidbits.com/53dc1fce-b712-4618-afb4-c94259665cca

[GaWx]

 12Z UKMET: center passes just SE of Bermuda
 

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER  36 HOURS
              FORECAST POSITION AT T+ 36 : 19.4N  49.2W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    0000UTC 18.09.2025   36  19.4N  49.2W     1008            42
    1200UTC 18.09.2025   48  20.2N  51.3W     1007            37
    0000UTC 19.09.2025   60  21.1N  53.9W     1007            33
    1200UTC 19.09.2025   72  21.6N  56.5W     1008            28
    0000UTC 20.09.2025   84  22.8N  58.1W     1008            31
    1200UTC 20.09.2025   96  24.1N  59.6W     1009            30
    0000UTC 21.09.2025  108  25.8N  59.8W     1008            37
    1200UTC 21.09.2025  120  27.3N  61.2W     1005            46
    0000UTC 22.09.2025  132  28.8N  62.3W     1003            44
    1200UTC 22.09.2025  144  30.3N  63.0W     1001            44
    0000UTC 23.09.2025  156  31.7N  63.0W     1000            49
    1200UTC 23.09.2025  168  32.5N  61.5W      998            43

[GaWx]

More 12Z runs:

 The models have switched in some cases. The GFS/CMC moved W to just SE of Bermuda whereas the Euro moved E to well E of Bermuda.

Icon: still well to the SW of others with it much weaker SSW of Bermuda then recurving NW

JMA: TS at Bermuda at 192