ATL: HELENE - Models

[BobHarlem]

0z GFS Cat 4 landfall near Perry, FL, good shift right from 18z (Where it was at Apalachicola).

[Steve]

pivotal weather

You won’t see that every day. Difference is cut off low interaction is way farther south. Plausible but a little out of the blue.

https://www.pivotalweather.com/model.ph ... &dpdt=&mc=

Not entirely out of the blue as the 00z NAM (using only for the large scale pattern, not storm track) made a similar adjustment.

Yeah because the cut off now is all the way into Tennessee on the NAM. But nothing anticipated that at 12z. It was all AR or OK. This should move up and out if NAM and ICON are right. It’s not fujiwara but both are cool to see and unique for late September. Been posting for a couple days I didn’t think surprises were over. And they’re probably still not. But consider

https://www.tropicaltidbits.com/analysi ... 92300&fh=6

[Fancy1002]

Can anyone point out why the intensification seems to halt. Is it an ewrc?

[Category5Kaiju]

GFS now shifts to the right. Looks like it's a faster, more aggressive trough this time around that causes the shift

[StPeteMike]

Well I stayed up long enough to see the GFS and I wish I went to sleep. Tomorrow is going to be crazy and if the 06z keeps the same set-up, I’ll expect the Tampa region and Nature Coast to start getting a little antsy.

Night board!

[wx98]

Very interesting shifts east in the ICON and now the GFS. Will wait to see if it’s a trend that will hold or if they shift back west at the end. We’ve seen both scenarios before…

[DunedinDave]

GFS now shifts to the right. Looks like it's a faster, more aggressive trough this time around that causes the shift

If that trough digs down like that, I wouldn’t be surprised if it kicks it further right. That trough really drops.

[Pelicane]

Usually storms like this get driven due east by a front. Having this get pinwheeled by a cutoff low in that location is not something I've seen before.

[BobHarlem]

0z GFS then moves it near Atlanta still with a cat 3 pressure (967mb) and still hurricane strength over East Tennessee. Inland folks are not going to be prepared for this.

[Fancy1002]

CMC also seems to be east southeast of the previous models

[cheezyWXguy]

Can anyone point out why the intensification seems to halt. Is it an ewrc?

Most likely just how it interacts with the trough. The difference between weakening, maintaining, and strengthening into landfall will probably be determined by fine details that probably can’t be well resolved yet. I will say though, while I don’t take simulated satellite seriously on these models, I find it interesting that the gfs shows the deepest convection on the western eyewall into landfall. This is the kind of structure that you tend to see with storms that strengthen or maintain in these setups since they are able to effectively rotate convection upshear (e.g., Michael, Ian, Laura, etc). Panama City to Sarasota should be paying attention to this at least as much as the rest of the panhandle imo

[USTropics]

Launching point begins to really matters here. The 00z icon has the bulk of the vorticity just off the western tip of Cuba in 60 hour:


GFS shows a much more consolidated core already and shoots the gap closer to the Yucatan Peninsula:


Both have an eventual interaction with the cutoff low:

[Poonwalker]

Naples and Fort Myers will need to be on guard if this gets yanked east.

[ineedsnow]

0z GEFS shifting east

[BobHarlem]

GFS has hurricane force winds scraping the Tampa Bay area with that big bend landfall, 97L is going to be large.

 https://twitter.com/BigJoeBastardi/status/1838070260882174369

[Blown Away]

Models slowly smoothing that hard W to WNW movement between @hours 18-60 into more NW movement resulting in 97L not being as far W near Yucatan tip and more near W Cuba before the NE turn. If this trend continues the area between Naples to Tampa will be on watch. IMO, that has been the trend change today.

[Blown Away]

00z HMON & HWRF already E of 18z through 48 hours…

[MarioProtVI]

HAFS-B nukes the sh!t out of this and goes for a full-blown Cat 5 stronger then Michael.

[ElectricStorm]

Luckily these hurricane models, especially the HAFS, can be pretty off before a TD actually forms. Really hoping that's the case here because both HAFS A and B runs would be downright devastating

[ElectricStorm]

HMON joins in with 909mb near landfall... winds "only" mid-range Cat 4