ATL: HELENE - Post-Tropical - Discussion

[kevin]

The latest center pass by the NOAA plane found a minimum pressure of 999.7 mbar with a minimum FL wind of 7 kt in its vicinity, which would translate to a current intensity of 999 mbar. Seems like there is slow strengthening over the last hours of about ~0.5 mbar/hour.

[Category5Kaiju]

Just for fun, I went back and did some research on Hurricane Ian. Around 48-60 hours before it made landfall near Fort Myers, the NHC had it making landfall some 150 miles north around the Pinellas/Pasco border. In fact, most all the models had it going right through Tampa Bay with hardly any going through Fort Myers. It didn't change until it officially made that right turn earlier than expected and it was a harder right turn than they thought.

And I know Charley did the same thing with a less turnaround time but I brought up Ian because modeling and forecasting is supposed to be so much better in the 2020s than 2000s and it's more recent.

So things can still change a lot either direction and I wouldn't be shocked if they do.

For some reason, storms just off the west coast of the Florida Peninsula tend to do this, where they hook east in the end more than expected. I don't know what this future system's story will be in the end, but I personally do think this phenomenon is important to keep in the back of one's head, especially considering it's fall now, when troughing tends to be more amplified and faster.

[xironman]

Still in a very sharp shear gradient.
She will probably not strengthen much today.

Shear has played a roll for the last few days. Curious to see what happens when she makes it to the Gulf.

Shear is forecast to drop off today as the ULL over the Yuc weakens. If that occurs, we should start seeing increasing organization today.

You can see the cirrus is starting to blow off west of north rather than east. The ULL is south. This vector is much more beneficial for the storm.

[NDG]

All I have to say regarding the forecasted track is to watch the GFS's trend over the next 24-36 hours, it nailed the track of Francine a good 48 hrs before landfall when all other major models and consensus models were well west. At this point I wouldn't be even taking the EC under consideration because of how bad it did on my books with Francine.

[kevin]

AF300 measured much higher winds in the NE quadrant (where the convection blow-up was over the last hour). 52 kt FL winds and 41 kt SFMR. NOAA3 also found 49 kt FL winds. Together this is sufficient to raise the current intensity to 45 kt, even though I guess NHC doesn't like to jump too much in one go so they'll go with 999 mbar / 40 kt. I know that I'm a bit less reluctant to pull the trigger on this system than the NHC seems to be, but this seems like an easy bet for TS Helene at 11am.

[Frank P]

Shear is forecast to drop off today as the ULL over the Yuc weakens. If that occurs, we should start seeing increasing organization today.

You can see the cirrus is starting to blow off west of north rather than east. The ULL is south. This vector is much more beneficial for the storm.

https://i.imgur.com/ezEDNct.gif

Looking at that loop and in order for this to hit the west tip of Cuba it going to have to make a hard right turn, unlikely IMO.

[kevin]

Current visible of the system:

[cycloneye]

Highest winds found so far from AF plane is Peak Flight-Level Winds: 52kt at 12:48z

[BIFF_THE_UNRULY]

i wont sleep better in Tampa or anywhere else is south florida till the storms develops and start moving north and models are still firm set on the nature coast.

Next 24 hours are a big deal here

[fllawyer]

In the "I'll take as much good news as I can get" camp, it seems like the current shear picture is the worst its been in the last 24 hours. Unfavorable shear now extends NW of the yucatan and also near the panhandle.



This was 24 hours ago:

[skillz305]

i wont sleep better in Tampa or anywhere else is south florida till the storms develops and start moving north and models are still firm set on the nature coast.

Next 24 hours are a big deal here

At this point I trust the consensus that this is headed towards the big bend

[NDG]

First squalls arriving in Cancun, live webcam:

https://www.youtube.com/live/tlRVK1opGX ... aDHCagt7on

[cycloneye]

Breaking news:, 12z Best Track changed the winds up to 40kt.

AL, 09, 2024092412, , BEST, 0, 194N, 837W, 40, 1000, DB

[Weatherboy1]

The latest center pass by the NOAA plane found a minimum pressure of 999.7 mbar with a minimum FL wind of 7 kt in its vicinity, which would translate to a current intensity of 999 mbar. Seems like there is slow strengthening over the last hours of about ~0.5 mbar/hour.

Yes. And it looks like the center is now getting "covered" by new convection as the ULL over the Yucatan moves/fills in. Think we start dialing up intensity now, and we have a TS at 11 am...

[wxman57]

I'd pay close attention to the ICON model. It did better than any other model for Beryl an Francine. It takes the center pretty close to Tampa on Thursday. Close enough for near hurricane force wind and a 10-12 ft surge.

[StPeteMike]

Breaking news:, 12z Best Track changed the winds up to 40kt.

AL, 09, 2024092412, , BEST, 0, 194N, 837W, 40, 1000, DB

If we don’t have TS Helene by 11, I’m going back to bed lol.

[TallyTracker]

I see a lot of talk about the right hooks many storms make on approach to landfall along the west coast of Florida and the Big Bend. I was thinking that was likely to occur too; however, one item sticks out as a difference to those situations. The upper low over the southeast is going to impart a NW motion after landfall. A right hook followed by a left hook means I think the track forecast could more likely error in either direction versus the normal trough pulling the storm northeast.

[psyclone]

Tapping fingers....awaiting a wxman57 post... Tell me I'm not the only one...

Edit to state I see he just posted...me no likey that one

[xironman]

Breaking news:, 12z Best Track changed the winds up to 40kt.

AL, 09, 2024092412, , BEST, 0, 194N, 837W, 40, 1000, DB

If we don’t have TS Helene by 11, I’m going back to bed lol.

Plenty of west winds to define the center

[Pipelines182]

I'd pay close attention to the ICON model. It did better than any other model for Beryl an Francine. It takes the center pretty close to Tampa on Thursday. Close enough for near hurricane force wind and a 10-12 ft surge.

it seems like every storm a different model handles it better than the last