ATL: PETER - Models

[SconnieCane]

If 95L is as weak as the GFS has been suggesting when it reachs the Carribean 95L will have a very hard time surviving the TUTT and wind shear.

What's up with all this shear in/near peak season, in a Nina? I'd say it was just the GFS doing that thing where it always wants to default to a Nino-like pattern at longer ranges for some reason, but this isn't really in the long range anymore.

[Ubuntwo]

6z EPS has some redevelopment post-TUTT.

[aspen]

It appears that interaction with the TUTT is key in determining how strong 95L will get east of 60W and whether it'll survive the shear or not. In the very weak 18z 9/15 HWRF run, 95L gets stuck right under strong NW upper-level flow and can only peak as a weak TS.


In today's 06z run, 95L and the TUTT are positioned just right where the TUTT opens a poleward outflow channel while there is low (<20 kt) UL flow behind it. While this isn't nearly as favorable as being under an anticyclone, it does seem conductive for some level of intensification before shear picks up sometime on Tuesday.


While different runs from the GFS and HWRF show significant variation on how 95L interacts with its UL environment and how strong it gets over the weekend in Monday, one thing that does seem to be shown across all models with MDR development is the reduction in UL winds from behind the system. Starting Friday night into early Saturday, the UL environment becomes more favorable, and 95L becomes a TC 12-24 hours later. This will be something to watch, because if we don't see 95L improving between 18z tomorrow and 12z Saturday, it would mean it won't get strong before the TUTT and probably won't even at all...at least before 60-65W. A TC forming further west like on the CMC model is possible in this scenario.

[Category5Kaiju]

Yeah perhaps the NHC marked the disturbance having a chance of forming too early? A lot can change, but at this point until it's a done deal and I see it actually dissipate I won't rule out more west-based development, even if the probability is low. I understand why many are skeptical of 95L's future, but in scenarios like this where the future of the storm is basically unknown even for the pros and dependent on many minor details, the fact that it is September, that the sst anomaly profile is now a classic, potent +AMO, and that we are highly likely headed toward a moderate La Nina with what looks to be a bona fide La Nina in the cards (and not a Modoki La Nina as the Nino 1,2 regions are solidly below average in sst anomalies), I would personally still keep an eye on this system for the forseeable future. Because, again, who knows? This has been one very weird invest.

[Blown Away]

12z...

[Blown Away]

06z HWRF back with a near Cat 3 Hurricane heading for NE Caribbean...

[ElectricStorm]

HWRF is usually trash until the center actually forms and we have a TD/TS. I'm going with the weaker solution for now. Only way I see this getting strong is if it makes it past the TUTT and redevelops, which is a possibility.

[gatorcane]

The CONUS should be thanking 96L which looks to turn 95l north into a weakness at least that is what the 12Z GFS depicts.

[blp]

12z GFS is similar to the Euro both have 96l hang around and create the weakness.

[otowntiger]

https://i.imgur.com/5zWNhxd.gif
06z HWRF back with a near Cat 3 Hurricane heading for NE Caribbean...

Looks to me like its actually heading such that it will miss the islands to the North East.

[aspen]

The 12z ICON is an absolute mess off the east coast at the end of its run. 96L is still hanging around, 95L is just north of the islands, and there’s a third TC forming off the Mid-Atlantic coast.

[aspen]

The CMC has a potentially very dangerous progression: 95L stays weak and fast, passing through the TUTT and getting north of the GAs by Tuesday where it starts to develop en route to the Bahamas. 96L stalls further east than on the GFS, meaning it won’t suddenly yank 95L due north or NNE. This setup could lead to a storm undergoing RI into the Bahamas without an exit route far enough east to keep it away from land.

Update: there is an escape route this run with ex-96L wandering around and a trough coming in, but a CMC-like setup is quite worrisome because who knows how far west 95L could get.

[Spacecoast]

[otowntiger]

The CMC has a potentially very dangerous progression: 95L stays weak and fast, passing through the TUTT and getting north of the GAs by Tuesday where it starts to develop en route to the Bahamas. 96L stalls further east than on the GFS, meaning it won’t suddenly yank 95L due north or NNE. This setup could lead to a storm undergoing RI into the Bahamas without an exit route far enough east to keep it away from land.

Update: there is an escape route this run with ex-96L wandering around and a trough coming in, but a CMC-like setup is quite worrisome because who knows how far west 95L could get.

, ehh I don't think it looks too worrisome to me. 1. It manages to stay well clear of the Bahamas and 2. its the CMC.

[gatorcane]

The CMC has a potentially very dangerous progression: 95L stays weak and fast, passing through the TUTT and getting north of the GAs by Tuesday where it starts to develop en route to the Bahamas. 96L stalls further east than on the GFS, meaning it won’t suddenly yank 95L due north or NNE. This setup could lead to a storm undergoing RI into the Bahamas without an exit route far enough east to keep it away from land.

Update: there is an escape route this run with ex-96L wandering around and a trough coming in, but a CMC-like setup is quite worrisome because who knows how far west 95L could get.

Looks like the Euro has big trough a over the EC a week from now which also keeps 95l away, not to mention it shears 95l out:

[SoupBone]

The CMC has a potentially very dangerous progression: 95L stays weak and fast, passing through the TUTT and getting north of the GAs by Tuesday where it starts to develop en route to the Bahamas. 96L stalls further east than on the GFS, meaning it won’t suddenly yank 95L due north or NNE. This setup could lead to a storm undergoing RI into the Bahamas without an exit route far enough east to keep it away from land.

Update: there is an escape route this run with ex-96L wandering around and a trough coming in, but a CMC-like setup is quite worrisome because who knows how far west 95L could get.

Looks like the Euro has big trough a over the EC a week from now which also keeps 95l away, not to mention it shears 95l out:

https://i.postimg.cc/pVpShxzb/ecmwf-z500a-Norm-atl-fh72-168.gif

It's beginning to be that time of year so that wouldn't be surprising.

[MJGarrison]

Happy Hour GFS used to be 5:30 on the dot. Have times changed slightly or its always just been a little random?


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[Ubuntwo]

18z GFS showing some consistency with a mid-grade TS 60 hours out.

[SouthFLTropics]

At 144 hours the 18z GFS has a much weaker 95L just north of Puerto Rico. This is a very precarious position if 96L lifts out and the ridge builds in.

EDIT: Despite what 96L does, it looks like a shortwave drops in from the west and will keep the ridge from building in.

[toad strangler]

At 144 hours the 18z GFS has a much weaker 95L just north of Puerto Rico. This is a very precarious position if 96L lifts out and the ridge builds in.

EDIT: Despite what 96L does, it looks like a shortwave drops in from the west and will keep the ridge from building in.

Even so, vorticity in whatever form actually comes about has a good shot at making it to at least 65W