Tropical Wave in the Central Atlantic (10/60)

[LarryWx]

I will say even if this goes slightly north of the islands like what the 12z ICON shows , its far from a guarantee that it would recurve like ERIN, the pattern gets murky because the bermuda high noses into florida unlike erin where the break in the ridge was around the bahamas, their is a trough on the models coming down thats another player, but that has had a lot of variability from run to run on the global models, this one is a bit murkier in terms of a recurve or not

The 12Z Icon 180 hour map along with hour 180 Icon steering features including at H5 would appears to me to suggest a sharp recurve is about to commence fwiw. Sharp enough to avoid the E coast? Quite possible but impossible to know, especially for OB and Cape Cod. But details not important on 180 hour operational run, regardless.

[LarryWx]

12Z UKMET: recurve with it moving NNW at end and aiming toward area around Bermuda:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 96 HOURS
FORECAST POSITION AT T+ 96 : 15.7N 54.7W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 21.08.2025 96 15.7N 54.7W 1009 28
0000UTC 22.08.2025 108 17.2N 57.2W 1007 28
1200UTC 22.08.2025 120 19.3N 60.2W 1006 30
0000UTC 23.08.2025 132 20.8N 61.9W 1006 32
1200UTC 23.08.2025 144 22.4N 63.8W 1005 35
0000UTC 24.08.2025 156 25.0N 64.5W 1005 41
1200UTC 24.08.2025 168 27.9N 65.8W 1005 43

[TampaWxLurker]

12z GFS so far thru 156 hrs a bit further north, more disorganized, over the Greater Antilles.

[AutoPenalti]

GFS a lot weaker, just an open wave at this point.

[Sambucol2024]

When will we get a number for this system?

[Stratton23]

GFS does develop after it gets out of the islands, a weaker storm will tend to move further west, TS in the gulf moving NW at day 9, misses the trough to its north

[TomballEd]

Looking at the persistent trough in the Ohio Valley with winds from the W at 500 mb in Florida, the ICON storm will absolutely recurve. GFS is are a bit S and a bit weaker, and its ridge over the top is keeping the trough from pulling it. Hence, into the Gulf. GFS keeps the storm from going crazy, likely due to dry air around the storm. That would also keep the relative size of the storm smaller.

By not going crazy, I mean a possible Cat 3 major hurricane vs a Cat 4 or 5 major monster. ICON and a recurve or GFS into the Gulf, 7 to 10 days out, I'm not choosing any one op because it did well with Beryl. At this point, I'd kind of merge the mean track from the GFS and Euro ensembles.

GFS map because ICON doesn't have the PWAT or mid level moisture maps. Dr. Cowan uses moisture forecasts a lot in his videos.

[Stratton23]

man that would be a brutal run for New orleans, cat 3 meandering around inland with weak steering

[mcheer23]

GFS- Gulf
Icon- near Florida
All others- OTS

[Stratton23]

Looks like alot will be determined by how much the bermuda high builds back in after Erin Departs, models obviously are very divergent on that, but we will know more in a few days, but folks in the gulf- east coast should definitely pay close attention to this, of course it could go out to sea, but this doesn’t appear to be a clean upper air pattern that would easily turn this out to sea , lots of murky details that need to be ironed out by the modes

[emeraldislenc]

Up to 30 % at 2 according to NHC!

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sun Aug 17 2025

2. Central Tropical Atlantic:
A tropical wave located near the Cabo Verde Islands is producing
disorganized showers and thunderstorms. Some gradual development of
this system is possible during the middle to latter portion of the
week while the system moves westward to west-northwestward at 15 to
20 mph across the eastern and central tropical Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

[Keldeo1997]

 https://x.com/NDGMETCHEF/status/1957153649123037589



This might be important for this. Models might underestimate the ridging because they don't see the cooler water temps from Eirn's wake creating sinking motion in the sub tropics and makes it easier for the bermuda to build back in.

[TomballEd]

GFS Gulf solution has some support from its ensembles but I think it is out on an island. I think the protective trough that captured Erin will persist long enough to recurve the AOI.

Looking at GFS ensemble heights, maybe after Day 11 the trough retrogrades back into the Ohio Valley, which sets up Florida/SEUSA for possible tropical hits although I think by then things will be quieting down for a week or two. There are a few GFS ensemble members that sneak future 99L under the ridge and into the Gulf. But not many. More long track/CV storms recurve than not. I'm assuming fish, but nothing over a week away is carved in stone.

The longer it takes to develop, the better chance it does have to maybe miss the trough and affect CONUS.

[Stratton23]

Still over a week out, folks in Texas to the SE coast need to be watching how models evolve over this week

[Jr0d]

The GFS is the outlier, surprise surprise. Even the GFS ensembles show a lot of recurves before Florida but we know the operational model likes to Give Florida Storms.

While the ICON is further west/left that the others, I can't see it going anywhere but north with the trough it currently is showing on the last frame of it's latest run.

It does seem like a strong trough for late August that they are projrcting but its hard to argue with the consensus. Of course its way to early to make a reasonable forecast, especially before we even have a low center to track.

At least this one is currently forecast to remain weak if it impacts the Carribean Islands. The chances of the GFS being correct and this making it to the Gulf of Mexico are slim to none in my amateur opinion.

Regardless it is that time of year where we can't turn our back anything.

[TomballEd]

Euro is 100% recurve. Just saying.

To be fair, there are a couple of W outliers that could threaten the Carolinas. I'd say the threat in the Houston area isn't zero, but it is a pretty small number

[Stratton23]

difference between the euro and GFS is the latitude in which the models start developing this thing, to be noted the GFS obviously is way more south than the Euro with it staying weak on approach to the leeward islands and caribbean, I have to lean toward potentially the more southern GFS solution because looking at the wave live on satellite imagery convection is really favoring the southern part of the wave, pretty void on the north end of the wave axis , something to keep in mind

[IcyTundra]

There will probably be an East Coast trough in that 7-10 day range the big questions are going to be how much will it dig and how quickly it moves out. It is also going to matter what portion of the wave develops and how quickly it develops. If the southern portion of the wave develops that would increase the odds of impacts to land. The same is true if development takes a little longer than the models are suggesting.

[LAF92]

The Euro has been bad all year playing catch up it seems. Not sure I’d put a lot of stock into the Euro until it actually shows some merit

[cycloneye]

 https://x.com/dmorris9661/status/1957175018447663199