Unsurprisingly, this evening the NHC designated the area of interest in the eastern Atlantic as Invest 92L.
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Fri Jun 16 2023
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
1. Eastern Tropical Atlantic:
A tropical wave located several hundred miles south of the Cabo
Verde Islands is currently producing a broad area of disorganized
showers and thunderstorms. Environmental conditions appear conducive
for additional development, and a tropical depression is likely to
form by the early to middle portion of next week while the system
moves westward at 15 to 20 mph across the eastern and central
tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...70 percent.
Forecaster Papin
TC genesis still needs to occur, but thus far this has been a remarkably well forecasted window for development, which @GaWx notes is highly anomalous against the historical record. There are a few reasons why this seems to be a very favorable window for development in the next week.
First, SSTs are historically warm for this time of year. It's warm throughout the basin, but in the MDR it is particularly hot.
Much higher than normal SSTs have allowed the MDR to be conducive at least thermodynamically.
Why? In large part because of the mid/upper level pattern we haven't seen strong trade winds, or SAL, to temper warming in the MDR east of the Antilles.
Just as important, we see a highly anomalous amount of OHC throughout the basin. This is a gif I quickly put together showing OHC values from 2016-2023 in mid June.
And today's value as a single image:
This is only one piece of the puzzle, however. In this region we also have reduced shear, and higher moisture levels, critical elements in TC development and survival that are usually hostile this time of year. It's about as good as it gets, currently.
Here's the 12z EPS using 5 day averaged wind shear anomalies. This is an incredible look that has trended more favorable in recent days.
Just as impressive is the moisture envelope. In recent years, dry air and stability put a cap on TC genesis and development, especially in the central and eastern MDR. That does not appear to be an issue this time, which again, is extremely impressive for mid-June.
Coupled with the passage of a CCKW, and this all leads to a highly favorable environment IMO for TC genesis. This would be a highly favorable environment in September.
It doesn't look like much now, but ASCAT shows that while elongated, it is trying to gradually consolidate. I think it will, and from there it'll be a question of
1) how quickly 92L can take advantage of the favorable environment, and
2) what the longer range steering pattern evolves into
There's not much more to say yet, other than the operational guidance has become more bullish on intensification in the last 24 hours for the above reasons.
As for track, while both ensembles (EPS/GEFS) look to favor an eventual recurve, it is extremely early to look long range on steering, though climo almost always favors a recurve, especially in the current upper level regime.
I would watch closely in the Antilles.