ATL: HELENE - Post-Tropical - Discussion

[Hypercane_Kyle]

Absolutely explosive thunderstorm development happening over the CDO. Some of the coldest cloudtops I’ve seen in the Atlantic since Iota in 2020.

[KC7NEC]

Update: My colleague and I arrived at the resort in St. Pete Beach yesterday, and the conference was cancelled about two hours later. Fortunately, most of the attendees (around 1,000 people) weren’t scheduled to arrive until Thursday, so they’ve canceled their plans. There are about 20 of us here now, and we’re likely staying to ride out the storm tonight and tomorrow. Most of us have flights tomorrow, but it’s doubtful they’ll happen. The biggest concern right now is the storm surge along the beach. I’ve got my ham radio ready, and since the storm is tracking further west, I don’t expect the resort to require an evacuation. While I’m not entirely certain what to expect, I think we’ll be okay. I’ll post updates as I can. Anyone in the St. Pete Beach area, feel free to reach out. Looks like my bucket list might get checked off tonight!

[xironman]

Here is a timelapse of the last ~3 hours with radar data from Cuba in the bottom left (keep in mind, the radar is analyzing mostly mid level features at that range):
https://i.imgur.com/W5TMBJq.gif

You have to wonder what the odds are of a near perfect pass though the channel.

[kevin]

The core is going nuclear on visible, look at those gravity waves in the last half hour. Kinda reminds me of Delta 2020.

[WeatherBoy2000]

 https://x.com/DCAreaWx/status/1838921431494627685



Looks like it's about go time for Helene.

[tulum07]

Does anyone know if Palm Beach District schools will be closed tomorrow, 9/26/24?

[Kingarabian]

Winds are certainly lagging its satellite appearance. Dvorak is easily a 4.5 right now. Center is in the middle of the CDO.

[REDHurricane]

The core is going nuclear on visible, look at those gravity waves in the last half hour. Kinda reminds me of Delta 2020.

Hopefully the brief land interaction with the Yucatan will slow things down for a bit, but I'm guessing the effect will be marginal at best. Before it enters the Gulf, anyone want to guess at what Helene's' peak pressure/wind speed will be? I'm gonna go with with 915mb/160kt, though if I were setting an O/U line I'd probably put it around 935mb/130kt right now

[GCANE]

Huge helicity with that long-duration hot tower

[GCANE]

3000 CAPE directly in the core

[kevin]

The core is going nuclear on visible, look at those gravity waves in the last half hour. Kinda reminds me of Delta 2020.

Hopefully the brief land interaction with the Yucatan will slow things down for a bit, but I'm guessing the effect will be marginal at best. Before it enters the Gulf, anyone want to guess at what Helene's' peak pressure/wind speed will be? I'm gonna go with with 915mb/160kt, though if I were setting an O/U line I'd probably put it around 935mb/130kt right now

Still feels a little tricky due to potential land interaction. After Yucatan I think estimates will be more accurate. Because of this slight uncertainty I'm a bit reluctant to outright call for a cat 5 now. I'm leaning towards a blend of all hurricane models except HWRF, which gives me 928mb/135kt.

[GCANE]

The newly forecasted cutoff low centered along the southern end of the MS river will likely cause the forecast track to shift more west

what is the CAPE looking like and should we be worried about tornado outbreaks in central florida?

4000 CAPE in the east GOM
Too early to tell about tornadoes

[aspen]

The core is going nuclear on visible, look at those gravity waves in the last half hour. Kinda reminds me of Delta 2020.

Thankfully, Helene’s core under the hood is a lot larger and broader than Delta’s, so we shouldn’t see Delta/Wilma levels of RI.

[CronkPSU]

The newly forecasted cutoff low centered along the southern end of the MS river will likely cause the forecast track to shift more west

what is the CAPE looking like and should we be worried about tornado outbreaks in central florida?

4000 CAPE in the east GOM
Too early to tell about tornadoes

in case it gets lost later, thank you so much for your constant updates during these storms, much appreciated

[SconnieCane]

May or may not be a technical landfall, but Helene's core is certainly causing impacts on the northeast coast of the Yucatan including Cancun. Any observations from there?

[DunedinNate]

When was the last Microwave scan? How big of a core are we talking here?

[ChrisH-UK]

Sunrise over Helene, it has developed well overnight and is getting rid of the ingestion of dry air, looks to be a big threat.

Source - https://col.st/DyGru

[toad strangler]

“Gigantic” hurricane developing…

 https://twitter.com/webberweather/status/1838927342699499652

[Steve]

May or may not be a technical landfall, but Helene's core is certainly causing impacts on the northeast coast of the Yucatan including Cancun. Any observations from there?

Visual, it's storming in Cozumel
https://www.youtube.com/watch?v=EE9013s31Hk

[USTropics]

May or may not be a technical landfall, but Helene's core is certainly causing impacts on the northeast coast of the Yucatan including Cancun. Any observations from there?

Based on radar and recon there is no direct landfall. Brian McNoldy at University of Miami has some amazing radar loops for current and past systems:
https://bmcnoldy.earth.miami.edu/tropics/radar/



Latest recon mission:


https://tropicalatlantic.com/recon/recon.cgi?basin=al&mapping=cesium

The NE coastline of the Yucatan peninsula is definitely feeling the effects. Rotating hot towers have been forming around the core and being dragged onshore: