Major Hurricane Helene

[Windspeed]

VDM reports a curved band in the NE quadrant. Core formation is most likely underway. Recon should make another pass and we'll see how quickly that is evolving while they're down there:

664
URNT12 KNHC 250620
VORTEX DATA MESSAGE AL092024
A. 25/05:54:30Z
B. 20.30 deg N 085.93 deg W
C. 850 mb 1321 m
D. 986 mb
E. 080 deg 8 kt
F. NA
G. NA
H. 51 kt
I. 053 deg 32 nm 05:44:00Z
J. 119 deg 58 kt
K. 049 deg 45 nm 05:40:00Z
L. 52 kt
M. 227 deg 25 nm 06:02:00Z
N. 325 deg 54 kt
O. 227 deg 36 nm 06:05:00Z
P. 18 C / 1522 m
Q. 26 C / 1541 m
R. 12 C / NA
S. 12345 / 08
T. 0.02 / 3 nm
U. AF300 0909A HELENE OB 05
MAX FL WIND 58 KT 049 / 45 NM 05:40:00Z
CURVED RADAR BAND IN NE QUAD, LESS THAN 50% COVERAGE
;

[Windspeed]

Second VDM. They're heading home.

211
URNT12 KNHC 250713
VORTEX DATA MESSAGE AL092024
A. 25/06:53:00Z
B. 20.29 deg N 085.86 deg W
C. 850 mb 1322 m
D. 985 mb
E. 355 deg 7 kt
F. NA
G. NA
H. 44 kt
I. 134 deg 23 nm 06:46:30Z
J. 226 deg 46 kt
K. 133 deg 31 nm 06:44:30Z
L. 65 kt
M. 311 deg 26 nm 07:01:30Z
N. 027 deg 51 kt
O. 312 deg 27 nm 07:02:00Z
P. 19 C / 1518 m
Q. 25 C / 1519 m
R. 14 C / NA
S. 1345 / 08
T. 0.02 / 2.5 nm
U. AF300 0909A HELENE OB 11
MAX FL WIND 58 KT 049 / 45 NM 05:40:00Z
LTG NW QUAD
;

[weatherCCB]

06z GFS 955mb @ landfall

06z Icon 946 @ landfall

[Seminole]

14 minutes ago, weatherCCB said:

06z GFS 955mb @ landfall

06z Icon 946 @ landfall

GFS near Perry Fl and Icon near Steinhatchee.  

[LongBeachSurfFreak]

Would love to be in Cancun right now. Outflow looks excellent now, I think this is about to go full tilt. RI today with some of the best OHC on the planet.

[olafminesaw]

Shrimpy West Pacifjc vibes.

[bdgwx]

SHIPS is now showing elevated RI probabilities. It's quick approach and land interaction may ultimately limit its potential though.

                                 *                  GFS version                   *
                                 * ATLANTIC     2024 SHIPS INTENSITY FORECAST     *
                                 * IR SAT DATA AVAILABLE,       OHC AVAILABLE     *
                                 *  HELENE      AL092024  09/25/24  06 UTC        *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120   132   144   156   168
V (KT) NO LAND    55    63    72    82    91   109   109    92    78    54    38   N/A   N/A   N/A   N/A   N/A   N/A
V (KT) LAND       55    63    72    82    91   109    75    42    32    28    28   N/A   N/A   N/A   N/A   N/A   N/A
V (KT) LGEM       55    61    69    77    86   103    76    41    31    28    27   N/A   N/A   N/A   N/A   N/A   N/A
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  EXTP  EXTP  EXTP  EXTP   N/A   N/A   N/A   N/A   N/A   N/A
 
 SHIPS Prob RI for 20kt/ 12hr RI threshold=  10% is   2.0 times climatological mean ( 4.9%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=  62% is   5.7 times climatological mean (10.9%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=  43% is   6.3 times climatological mean ( 6.8%)
 SHIPS Prob RI for 35kt/ 24hr RI threshold=  24% is   6.2 times climatological mean ( 3.9%)
 SHIPS Prob RI for 40kt/ 24hr RI threshold=  15% is   6.3 times climatological mean ( 2.4%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=  44% is   9.6 times climatological mean ( 4.6%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=  19% is   4.1 times climatological mean ( 4.7%)
 SHIPS Prob RI for 65kt/ 72hr RI threshold=   0% is   0.0 times climatological mean ( 5.3%)
    
Matrix of RI probabilities
------------------------------------------------------------------------------
  RI (kt / h)  | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48  |65/72
------------------------------------------------------------------------------
   SHIPS-RII:     9.6%   62.4%   42.5%   24.3%   15.0%   44.1%   19.5%    0.0%
    Logistic:    11.4%   36.9%   18.8%   12.0%    4.8%   15.4%    3.0%    0.0%
    Bayesian:    23.7%    5.9%    2.8%    3.3%    0.3%    3.2%    0.5%    0.0%
   Consensus:    14.9%   35.0%   21.4%   13.2%    6.7%   20.9%    7.7%    0.0%
       DTOPS:    22.0%   92.0%   77.0%   55.0%   30.0%   99.0%    2.0%    1.0%
       SDCON:    18.4%   63.5%   49.2%   34.1%   18.3%   59.9%    4.8%     .5%

 

[weatherCCB]

06z hurricane models coming with rapid deepening.

Buckle up

 

[Bhs1975]

Would love to be in Cancun right now. Outflow looks excellent now, I think this is about to go full tilt. RI today with some of the best OHC on the planet.

It's not going to have much time to take advantage of it. This will be a huge inland threat though.

[hawkeye_wx]

The center took the expected right turn over the last few hours.  It does not appear it will interact much with the tip of the Yucatan.

The latest extrap pressure is 981 mb.

[40/70 Benchmark]

7 hours ago, Windspeed said:

Here's a radar loop out of Cancun. The low-level and mid-level circulations look fairly aligned, but a core eyewall band has yet to evolve. Helene just isn't there yet as far as hurricane intensity. I'd say it needs at least another 12-18 hours for the organization to ramp up a core. Perhaps the Yucatán landmass may also aid in the LLC tightening due to friction. Also, it's going to be very close that the LLC doesn't actually cross over extreme NE Yucatán.

Absolute agreement.

[40/70 Benchmark]

7 hours ago, Radtechwxman said:

I agree and once that core is established I think that's when RI intensification phase will start

Yes.

[40/70 Benchmark]

5 hours ago, GaWx said:

 It looks like the 0Z Euro has the center crossing Gwinnett County in N GA, E/NE of ATL.
 
 The distance from landfall position to E of ATL is ~250 miles and it gets there in only 9 hours on the Euro. That works out to an average of a whopping 28 mph, among the fastest on record for that area! To compare, the very fast moving Opal averaged no more than ~25 mph. Eloise of 1975, which also brought damaging winds well inland to W GA, averaged at ~29 mph.

Opal was a much smaller system IIRC....this is going to be an extremely damaging storm and it can't be stressed enough how trivial the difference between 100 mph and 130 mph sustained wind is going to be. It will really just be a point of obsession for us dorks.

The surge will be immense.

[CoastalWx]

TLH could be in for a blow

[Windspeed]

Watching Helene evolve on radar out of Cancun and have only just realized that the echoes from there are somewhat deceiving. The mesos rotating towards Cancun that I thought were the onsets of a core are just that, mesos. I have been looking for a small initial core eyewall to develop. But the much larger LLC is indeed intensifying. Cuban radar shows this evolution much better. Helene has a large core developing. Notice the intense NE band while simultaneously strong cells are consolidating on the south side swiftly moving east. The Cancun radar appears heavily attenuated at the moment for some reason. Not sure if that is due to high wind or the array under high precipitation. Regardless, Helene is going to be a large hurricane.

Cancun radar:


Cuban radar:

[hawkeye_wx]

6 minutes ago, CoastalWx said:

TLH could be in for a blow

Solid west shift from the 06z Euro.

[BoulderWX]

Up to 70mph - we should have Hurricane Helene by the 11am advisory

 

[WxWatcher007]

26 minutes ago, hawkeye_wx said:

Solid west shift from the 06z Euro.

Spaghetti models are a touch west too. I do think there’s a limit to how west it can go given the steering pattern and how deep I think this’ll get, but TLH could be the bullseye. 

[MattPetrulli]

Ah yes, the classic 979 MB tropical storm. 

[Hotair]

 

Helene - CAT-TS 8 AM (EDT) Advisory Movement: NW @ 9 MPH Winds: 70 MPH Pressure: 979 MB

Friends who are staying at St. George Island are leaving this morning and tell me the owners have not returned their messages (are away in Europe).  The house is on pilings way high but their cars and other vehicles are parked below along with many of their things. 

[40/70 Benchmark]

2 minutes ago, MattPetrulli said:

Ah yes, the classic 979 MB tropical storm. 

I was about to say... the size of the system is already evident by the distorted wind-pressure relationship....the gradient is taking a long time ot build. Winds will likely respond quickly tonight as the core becomes established and tomorrow should be fun.

[SnoSki14]

40 minutes ago, 40/70 Benchmark said:

Opal was a much smaller system IIRC....this is going to be an extremely damaging storm and it can't be stressed enough how trivial the difference between 100 mph and 130 mph sustained wind is going to be. It will really just be a point of obsession for us dorks.

The surge will be immense.

This could be more impactful than the strong Cat 4-5 hits as of late. It's all about the size when it comes to tropical systems and this one is huge. 

[schoeppeya]

Certainly one of the most impressive satellite presentations I can remember for a tropical storm!

[tarheelwx]

If we get to 80 or so by 5pm and that is before any rapid intensification, what would be the top end potential?  There's been some crazy intensification in the gulf when there's such warm water.

TW

[40/70 Benchmark]

5 minutes ago, SnoSki14 said:

This could be more impactful than the strong Cat 4-5 hits as of late. It's all about the size when it comes to tropical systems and this one is huge. 

Yea, this is what I have been stressing.....systems like Charlie will pale in comparison to this even it hits as like a 2.

[bigtenfan]

Question for those on the board more knowledgeable than I am.

I see that the TS warning is extended all the way down the Florida east coast yet the  TS Wind speed probabilities for MIA. FLL and WPB are only 7, 12 and 14% respectively. If the probabilities are that low why does the TS warning extend down that far?

 

Thanks in advance.

[Hotair]

At over 50 miles away from the coast of Cancun local reports show outages and many trees down. A reminder this is a large system that will have significant impacts perhaps even hundreds of miles from the coc 

here in Tampa I am just hoping the storm gets steered quickly up and away from the area, but realistically we know South Tampa will be a wet mess for weeks to come 

[NeffsvilleWx]

3 minutes ago, bigtenfan said:

Question for those on the board more knowledgeable than I am.

I see that the TS warning is extended all the way down the Florida east coast yet the  TS Wind speed probabilities for MIA. FLL and WPB are only 7, 12 and 14% respectively. If the probabilities are that low why does the TS warning extend down that far?

 

Thanks in advance.

 

Keep in mind that "tropical storm wind speed" means sustained winds of TS force. It does NOT mean there will not be gusts meeting or exceeding sustained TS wind speeds. But a TS warning is not just about wind speed. The other threats need accounted for, too. Hence the TS warning.

[MANDA]

Everything looks on track.  Fully expect Hurricane status by 11:00 a.m. advisory.  Center will not landfall over the Yucatan.  Give it a little time to pull into the southern GOM and clear the influence of the Yucatan and we'll really be on the upswing. 

Surge going to be a big issue for a large area near and east of track.  FL west coast Tampa vicinity on north going to take a hit.  No joke...if ordered to evacuate you should go.  Inland wind and flooding going to be a big problem mainly for Georgia.  Expect massive power outages over a large area.

[TPAwx]

Surprised at the lack of Zone A evacuation orders for Hillsborough and Pinellas (they have a partial) Counties.  Surge and wind impact should be more amplified than the last two I-storms, had to evac for both.

edit - just issued for Hillsborough Zone A