Major Hurricane Helene

[GaWx]

Even though the Icon and GFS have similar landfall locations/strengths, the GFS landfall is a whopping 60 hours earlier (Thu evening) vs Icon (Sun morning).

[GaWx]

0Z GEFS is still another pretty ominous run for Pensacola to Tampa and inland NE from there. Fortunately most members are much weaker than the operational but still this isn’t a good sign.

[GaWx]

0Z Euro: east trend in this model too; similar strength to UKMET/CMC (989) with landfall Apalachicola Thu night (much closer to GFS’ Thu evening and UK’s Fri afternoon than Icon’s Sun morning). Gives 3-7” of rainfall to most of NW FL, GA, AL, TN as it moves N through W GA and TN

[GaWx]

0Z EPS: follows the faster and further E 0Z Euro but it is like the Euro still NW of the GFS suite with tracks centered on Apalachicola that then go N near the GA/AL line before curling back NNW. It is similar to the 0Z GEPS.

[CurlyHeadBarrett]

5 hours ago, MJO812 said:

Icon is devastating 

 

Jova if that happens

does it reach Tampa?

[Floydbuster]

 

[yoda]

06z GFS 961mb into FL Panhandle (near Panama City) at 114

[cptcatz]

8am up to 10/70 and we now have an X on the map.  Hopefully that means in invest is coming later today.

[GaWx]

6Z EPS mean shifted slightly W of its 0Z run mean (now a little W of AL/GA border vs about on that border)

 

[GaWx]

6Z Euro-AI shifted ~50 miles NW of its 0Z with it coming in to the middle of the Big Bend vs the far rt portion of it on the 0Z

[Amped]

Eps still has a lot of members near Tampa. 

[GaWx]

It is not finished, but the 12Z Icon is much faster and well E of its prior runs with it missing the Yucatan to the E for the first time. It look like it is going to be similar to the 0Z Euro.

[cptcatz]

16 minutes ago, Amped said:

Eps still has a lot of members near Tampa. 

Not seeing that. 06z has two members anywhere on the west coast of florida. All others are big bend and west. 

[purduewx80]

This cluster product valid on Thursday evening shows huge differences in where the cut-off is, which is unfortunate but to be expected in the blocking regime we're in now. It takes the Canadian, GFS and Euro ensembles, groups their 500 mb depictions into four similar patterns (the main 4 panel with colors) and also displays the ensemble mean on the lower left (upper low over northern AR). No one cluster is more likely than the others at this point, but watching trends in where the mean is will be important. The shading is just where the cluster has higher or lower heights than the mean. The upper low is predicted to be anywhere from the Ozarks to St. Louis to central OK, with cluster 2 showing something more akin to the EC-AIFS, with a more progressive cut-off and ridging in the Plains. There are really big differences with troughing over New England, too. Lots to sort out here still. These are the parts that will have some influence on the extent of rainfall to the west, its track/speed in the northeastern Gulf and especially the jet configuration for either shear or ventilation.

 

 

[GaWx]

The 12Z Icon is much quicker than its prior runs and is now much closer to the timing of the consensus. Although much further E early, this much quicker movement allows it to be captured by the cutoff H5 low and it then moves N to near Panama City at 984 mb late Thu night followed by a NNW move through AL.

[nvck]

 

Euro ensemble pressure matrices for Tampa and Pensacola, off the 00z run (not available on 06z). Looks to be angling at more of a panhandle/ big bend area landfall, although not super strong.

[GaWx]

12Z GFS just slightly E of 6Z but well NW of 0Z with ~942 mb near Panama City moving N

[purduewx80]

That's a good bit east of Panama City. 

 

[Seminole]

2 minutes ago, purduewx80 said:

That's a good bit east of Panama City. 

 

Right on top of my casa at St. George Island

[GaWx]

TT 12Z GFS SLPs ~8 mb lower than my source

[nvck]

7 minutes ago, purduewx80 said:

That's a good bit east of Panama City. 

 

obviously just one model run, but wow... 935 only 4.5 days out is nothing to sneeze at...

[GaWx]

16 minutes ago, nvck said:

obviously just one model run, but wow... 935 only 4.5 days out is nothing to sneeze at...

Fortunately Icon, CMC, and UKMET are much weaker though UKMET often is too weak this far out.

12Z UKMET: ~12 hours earlier landfall (Thu night) than and ~75 miles W of 0Z pretty close to Apalachicola at ~987 mb vs ~993 mb on 0Z:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER  42 HOURS
              FORECAST POSITION AT T+ 42 : 17.9N  85.5W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    1200UTC 24.09.2024   48  18.0N  86.0W     1003            29
    0000UTC 25.09.2024   60  18.2N  85.5W     1002            30
    1200UTC 25.09.2024   72  20.3N  86.2W      998            40
    0000UTC 26.09.2024   84  21.7N  86.2W      995            39
    1200UTC 26.09.2024   96  24.0N  86.0W      992            44
    0000UTC 27.09.2024  108  27.4N  85.1W      989            56
    1200UTC 27.09.2024  120  31.3N  84.7W      987            39
    0000UTC 28.09.2024  132  36.4N  84.7W      992            21
    1200UTC 28.09.2024  144  40.5N  87.2W      996            34
    0000UTC 29.09.2024  156  42.3N  91.4W     1000            21
    1200UTC 29.09.2024  168  39.0N  94.3W     1004            13

 

[GaWx]

GEFS: 12Z mean has a significant shift NW vs prior runs with many more going through AL vs earlier runs

[WxWatcher007]

Euro won’t be anywhere as strong as the outlier GFS, but it will come in stronger than the 00z run.

[GaWx]

1 minute ago, WxWatcher007 said:

Euro won’t be anywhere as strong as the outlier GFS, but it will come in stronger than the 00z run.

12Z Euro 982 Thu evening in vicinity of Apalachicola; Atlanta Fri AM at 992

[GaWx]

12Z EPS: mean landfall Thu night near Apalachicola and then it moves N fairly close to GA/AL border; many either W half of lower GA or E half of lower AL; mean a bit E of 6Z, which was in E AL and perhaps very slightly E of 0Z

[Normandy]

Starting to get a big westerly wind surge coming off Nicaragua.  Gyre is starting to crank now

[CurlyHeadBarrett]

40/80 already JFL @n9wiff

 

2. Northwestern Caribbean Sea and Gulf of Mexico:
Disorganized showers and thunderstorms located over the northwestern 
Caribbean Sea and portions of Central America are associated with a 
broad area of low pressure. Environmental conditions appear 
favorable for development of this system, and a tropical depression 
or tropical storm is likely to form during the next few days while 
moving northward across the northwestern Caribbean Sea and Gulf of 
Mexico. Regardless of development, this disturbance is expected to 
produce heavy rains over portions of Central America during the next 
several days. Interests in the northwestern Caribbean, Yucatan 
Peninsula of Mexico, and western Cuba should closely monitor the 
progress of this feature. Later this week, the system is forecast to 
move generally northward across the Gulf of Mexico, and interests 
along the northern and northeastern Gulf Coast should also monitor 
the progress of this system.
* Formation chance through 48 hours...medium...40 percent. 
* Formation chance through 7 days...high...80 percent.

[CurlyHeadBarrett]

Invest now 

mirin

 

AL, 97, 2024092218,   , BEST,   0, 153N,  832W,  20, 1007, DB

[Chinook]

NWS-WPC has a low on the map