ATL: HELENE - Post-Tropical - Discussion

[REDHurricane]

970 extrap. Hardly dropped at all

Not that surprising given the huge size, it'll probably really get going and close off an eyewall in maybe 4-8 hours or so? Takes a lot more fuel to fully power up a jet engine compared to a lawnmower

[ElectricStorm]

970 extrap. Hardly dropped at all

FWIW, the hurricane models all showed stable, or rising, pressure through the evening and early night. They did not start showing RI until between 06-09z. So we should start seeing pressures drop sometime within the next hour or so. It's current structure evolution also supports this as well.

0z hurricane models all had 963mb or lower by now so it's lagging pretty far behind them. We'll see how it evolves overnight

[Bocadude85]

Just took a gulp of dry air again

Doesn't look like dry air to me IMO, may just be the "outer eyewall" trying to clear out after all. On the 5-min loops you can seemingly see dual rotating hot towers around the outer eyewall.

No, there is a painfully large dry slot on water vapor and visible on the Eastern portion of the CDO. More than one actually.

I’m looking at water vapor and not seeing any dry air penetrating the core.

[AxaltaRacing24]

970 extrap. Hardly dropped at all

FWIW, the hurricane models all showed stable, or rising, pressure through the evening and early night. They did not start showing RI until between 06-09z. So we should start seeing pressures drop sometime within the next hour or so. It's current structure evolution also supports this as well.

0z hurricane models all had 963mb or lower by now so it's lagging pretty far behind them. We'll see how it evolves overnight

The HM0N/HWRF both had poor initializations, but the 18z/00z HAFS-A/B both had a good handle on it. They showed this trend for 2 runs in a row and essentially nailed the int. Both still show 940s at landfall, which seems like the realistic ceiling for such a large storm.

[NDG]

Recon shows only a slow drop in pressure with still not tight at all core.

[otowntiger]

970 extrap. Hardly dropped at all

FWIW, the hurricane models all showed stable, or rising, pressure through the evening and early night. They did not start showing RI until between 06-09z. So we should start seeing pressures drop sometime within the next hour or so. It's current structure evolution also supports this as well.

0z hurricane models all had 963mb or lower by now so it's lagging pretty far behind them. We'll see how it evolves overnight

thats great news. The longer it takes to get cranking the better. It would appear that there is a decent chance that it will under perform and hopefully be at least somewhat less of a menace. We’ll see.

[ElectricStorm]

FWIW, the hurricane models all showed stable, or rising, pressure through the evening and early night. They did not start showing RI until between 06-09z. So we should start seeing pressures drop sometime within the next hour or so. It's current structure evolution also supports this as well.

0z hurricane models all had 963mb or lower by now so it's lagging pretty far behind them. We'll see how it evolves overnight

The HM0N/HWRF both had poor initializations, but the 18z/00z HAFS-A/B both had a good handle on it. They showed this trend for 2 runs in a row and essentially nailed the int. Both still show 940s at landfall, which seems like the realistic ceiling for such a large storm.

That's fair I didn't go back and look at the 18z cycle. It's certainly still got time to reach the forecasted 115kts, and I think it will or at least get close, but it's still got some work to do structurally first, which may take the next several hours

[NDG]

Stronger winds in the SE quadrant.

000
URNT15 KNHC 260606
AF309 1409A HELENE HDOB 15 20240926
055900 2309N 08600W 6966 02959 9826 +099 +064 234055 056 059 011 00
055930 2307N 08559W 6964 02966 9830 +100 +063 235059 061 061 012 00
060000 2306N 08557W 6963 02971 9838 +097 +058 235063 064 063 016 00
060030 2305N 08556W 6980 02957 9858 +085 +056 235071 072 064 022 00
060100 2304N 08555W 6962 02981 9867 +080 +047 235071 073 065 023 00
060130 2302N 08553W 6957 02992 9865 +087 +048 234073 075 066 033 00
060200 2301N 08552W 6961 02994 9866 +093 +052 231079 080 065 034 00
060230 2300N 08551W 6960 02993 9872 +089 +050 232075 077 065 032 00
060300 2259N 08549W 6968 02993 9879 +091 +050 234074 076 068 023 00
060330 2257N 08548W 6966 02999 9876 +096 +047 235069 071 072 016 00
060400 2256N 08547W 6969 03000 9899 +082 +044 237071 072 074 029 00
060430 2255N 08545W 6948 03029 9892 +090 +048 230072 076 075 033 00
060500 2253N 08544W 6970 03004 9897 +087 +047 231066 076 085 029 00
060530 2252N 08543W 6967 03014 9907 +084 +049 229068 071 085 026 00
060600 2251N 08542W 6966 03017 9907 +087 +050 219070 074 084 016 00
060630 2250N 08540W 6971 03016 9907 +089 +044 223069 074 086 001 00
060700 2249N 08539W 6972 03017 9907 +092 +046 224069 070 086 003 00
060730 2247N 08538W 6966 03026 9909 +093 +046 224064 069 085 000 00
060800 2246N 08537W 6967 03028 9902 +103 +047 227061 063 083 000 00
060830 2245N 08535W 6967 03034 9909 +103 +049 224060 060 083 000 00

[CrazyC83]

That's the weaker side, so 85 kt might be reasonable now.

[ElectricStorm]

please delete

[ThunderForce]

When is this supposed to start turning NNE/NE? NHC has said it's been moving north for quite a while now.

[wx98]

Doesn’t look like much in the way of pressure falls just yet.

Wind is definitely up though. ~80 kt FL, 87 SFMR

[caneman]

When is this supposed to start turning NNE/NE? NHC has said it's been moving north for quite a while now.

You can see on the app zoom earth that it's now moving NNE. It's free and then click the tab to turn on wind animation

[Keldeo1997]

 https://x.com/webberweather/status/1839189085824356370

[ConvergenceZone]

If you would have told me this morning that we would only be looking at an 85 mph tonight I would have been shocked. It's going to have to ramp up quick if it's going to make it from cat 1 to cat 4 in 17 hours. It's still possible , but from now on every hour it doesn't intensify lessons that chance of it landfalling as a cat 4.

[caneman]

If you would have told me this morning that we would only be looking at an 85 mph tonight I would have been shocked. It's going to have to ramp up quick if it's going to make it from cat 1 to cat 4 in 17 hours. It's still possible , but from now on every hour it doesn't intensify lessons that chance of it landfalling as a cat 4.

Still 24 or more hours til landfall I believe. Still has time.

[ElectricStorm]

If you would have told me this morning that we would only be looking at an 85 mph tonight I would have been shocked. It's going to have to ramp up quick if it's going to make it from cat 1 to cat 4 in 17 hours. It's still possible , but from now on every hour it doesn't intensify lessons that chance of it landfalling as a cat 4.

Needs 45mph to get to 130, looks like that's about a 2.6mph increase every hour. That is very doable

[ConvergenceZone]

If you would have told me this morning that we would only be looking at an 85 mph tonight I would have been shocked. It's going to have to ramp up quick if it's going to make it from cat 1 to cat 4 in 17 hours. It's still possible , but from now on every hour it doesn't intensify lessons that chance of it landfalling as a cat 4.

Still 24 or more hours til landfall I believe. Still has time.

Really? I didn't know they moved up the landfall time to midnight Thursday. I must have missed that. The last I checked it was around 5:00 to 6:00 PM. Guess I need to go back and look.

[Bocadude85]

If you would have told me this morning that we would only be looking at an 85 mph tonight I would have been shocked. It's going to have to ramp up quick if it's going to make it from cat 1 to cat 4 in 17 hours. It's still possible , but from now on every hour it doesn't intensify lessons that chance of it landfalling as a cat 4.

Still 24 or more hours til landfall I believe. Still has time.

Really? I didn't know they moved up the landfall time to midnight Thursday. I must have missed that. The last I checked it was around 5:00 to 6:00 PM. Guess I need to go back and look.

The official NHC track is still offshore at 7pm central time.,

[rigbyrigz]

When is this supposed to start turning NNE/NE? NHC has said it's been moving north for quite a while now.

If you look at the Forecast discussion future-points over 36 hours, it moves almost due north for 12, then NNE* for 12, then almost due N for the last 12 hours. And the "outlooks" tend to say "north or north-northeast" but never says NE.

*in the second 12 hours actually moves up 4, right 1.5 = 69.4, when pure NNE is 67.5 ...just to show you it's on the North side of NNE.

Despite GFS and other models differing, these outlooks suggest landfall near St. Marks, about 60 nm west of Perry area, where earlier landfall points in the discussions (and GFS etc) suggested. Due to eyewall aspects, that modification lowered the NWS local forecast for Perry (inland Taylor County) from 80-100 with gusts to 120, to 40-45 with gusts to 65. (So these things matter to the locals!!)

As some suggest, the large wind field means Perry could still bear 100+ horrors, and the coastal Taylor (Keaton Beach, Steinhatchee) indeed says 60-80 gusts to 100 (and has been rising over the day.)

Of course, slowing, front interaction timing, wobbles, and such could see this change. I've sought to see what experts (or hobbyists here) say abt this enduring difference in path (and landfall) from NHC official discussions, versus most of the models (besides CMC?) ...no one seems to have an answer, still seeking, lol!