Tropical Wave in the Central Atlantic (10/60)

[Nimbus]

More convection this morning in the northern part of the wave near 13.5 N persistence is the key, might be an invest at 11 AM?

[BobHarlem]

Right now only 2-3 GFS ensembles show it impacting us land. Most now recurve, including the 6z operational, although it does get close to Bermuda. Effectively following or east of Erin's path. The elongated/multi center struggle really goes against anything developing. GFS doesn't even kick into development until it's near Bermuda. CMC/Icon/Euro still don't show any development--the euro attempts it near when it's east of Bermuda, but doesn't succeed, and there no euro ensemble members anywhere close to the US. It's likely the NHC starts dropping chances today, but probably won't drop it, it's still late August and there's still the chance that the southern area takes over more than the models are showing. I doubt they'll put an invest tag on it unless something changes.

[cycloneye]

Near the Leeward Islands in the Tropical Atlantic:
A tropical wave located over the central tropical Atlantic continues
to produce a broad area of disorganized showers and thunderstorms.
Environmental conditions appear conducive for gradual development of
this system, and a tropical depression could form toward the end of
the week or this weekend. This system should move westward to
west-northwestward at about 20 mph and approach the vicinity of the
Leeward Islands on Friday.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...60 percent.

[TampaWxLurker]

With Erin starting to slow down to a meandering pace, her size and continued presence is going to change the setup and timing of the ridge rebuilding. A few days ago it was forecast for Erin to be north of Bermuda and imminently swept out to sea by early Thursday. The latest NHC forecast now delays that into Friday.

Most models have this disturbance approaching the Leeward islands by the same time Friday. It'll depend on if the southern lobe that people have discussed develops instead of the northern lobe; but if it is the northern lobe, the opportunity SHOULD be there for anything approaching the northern Leewards to be able to use the exit being held open by Erin before the ridge builds back in. All thanks to Erin slowing down.

[wxman57]

Erin should leave a large trof in its wake, allowing a perfect avenue for this feature to recurve. May cause some thunderstorms across the NE Caribbean Friday-Saturday, but that may be about it. Models are backing off from development until maybe as it's recurving in the open Atlantic.

[Spacecoast]

The Euro has been very consistent about this being weaker system, and an earlier recurve. ..

As far as the GFS,... here's a small picture of a big cave.

[Jr0d]

.....and poof the GFS caved(again)

It does still have one ensemble member taking a 966mb storm over Cuba and eventually all the way across the GoM to Mexico.



The Canadian ensembles have a handful of lows making it to the NW Caribbean but I am not sure if its this aoi or 99L.

[Teban54]

The Cape Verde window is closing. I would give it a few more weeks and then eyes start shifting a little more to the Caribbean. Long term Euro doesn’t really seem to show anything threatening the US from the Cape Verdes. GFS seems to get Caribbean season going at the end of August although anything long-term GFS I mostly toss aside.

To say the CV window is closing 1 day before the actual peak season even begins is... quite something.

[cainjamin]

Reminds me a bit of pre-Isaias, which was another sprawling wave with multiple competing vorticity centres. Models showed it developing much more quickly initially until they got a better handle on its poor structure. I still think we'll get something develop out of this but it doesn't look like it will be the doomsday scenarios the GFS was forecasting last week.

[BobHarlem]

12z Icon now develops this north of the leewards, then kills it off close to Bermuda, sheared apart in Erin's wake.

[TampaWxLurker]

12z GFS is VERY disorganized through 138 hours. Basically a broad open wave lifting north after passing thru the Leeward and Greater Antilles.

[Stratton23]

Notice the trough lifts out before it can capture the wave, energy moving west toward the gulf as ridging builds in

[BobHarlem]

12z GFS you have to use the 850mb vorticity to see anything (it's late august right?), but you can tell the southern lobe eventually splits and it spits up into Erin's wake and the southern lobe into Gulf on the 12z. No development up to then anyway (unless that split fires up in the Gulf).

[TampaWxLurker]

NHC changed its graphic at 2pm so now the orange shaded area points out towards the open SW North Atlantic, east of where Erin is right now. Rather than the more east-west orientation it was previously in.

[USTropics]

12z GFS you have to use the 850mb vorticity to see anything (it's late august right?), but you can tell the southern lobe eventually splits and it spits up into Erin's wake and the southern lobe into Gulf on the 12z. No development up to then anyway (unless that split fires up in the Gulf).

This is a solid assessment, at the end of the day this area just had too many competing vorticity maxima to consolidate. 50W longitude right now is kind of the magical line—if vorticity doesn't consolidate before then the low-level flow acceleration into the Caribbean really gets cranking and it's nearly impossible at that point (the Caribbean graveyard effect). A wave fracture is the most likely outcome now.

[Stratton23]

USTropics might still be worth watching if something like the GFS is right and we get the wave to split into two pieces and once ends up in the gulf, probably wouldn’t do much, but still a scenario that would be worth watching if that were to happen with this

[cycloneye]

18z GFS develops this wave north of Puerto Rico.