Major Hurricane Helene

[SnowGoose69]

24 minutes ago, dbullsfan said:

This seems insanely tightly clustered this far out.


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By the old rule you wanna be in Atlanta or Apalachicola right now if you do NOT want to get hit by this.  You know, even in 2024 its never going to take anything close to that exact track, by that I mean still within 100 miles but 100 miles left or right is everything.

[SnowGoose69]

8 minutes ago, StantonParkHoya said:

Outside of Beryl, every other storm has struggled this year. Let’s hope that trend continues.

The problem is the dry air issue seems non existent this time so something else is going to have to save it. 

[StantonParkHoya]

5 minutes ago, SnowGoose69 said:

The problem is the dry air issue seems non existent this time so something else is going to have to save it. 

Shear forecast to increase as it approaches 

[allgame830]

10 minutes ago, StantonParkHoya said:

Shear forecast to increase as it approaches 

If Helene gets strong really fast that shear isn’t going to matter as much. 

[WxWatcher007]

I don’t think dry air is likely to be a major inhibitor (but watch for it still given the theme of the season) because I don’t think we’re going to get enough shear in the Gulf given storm motion to impart much before there’s a well organized inner core.

Unlike other storms, even if there’s a last minute increase, which didn’t weaken storms like Beryl and Francine, this one will be moving quite fast near the coast. Not much time to weaken imo. 

To me, the things that could keep this in check wind wise (and currently I think “high end” 2 seems to be the floor) are:

1) too much time organizing the next 48 hours and establishing an aligned vortex, which could be done with the current southwesterly shear in the Caribbean and/or

2) Early ERCs that promote the storm to expand substantially and become inertially stable, but with a much broader wind field. 

In fact, I think the earlier RI happens the more likely 2 becomes. To be sure still potentially higher end in this scenario, with surge impacts being enhanced along the west coast of Florida and peak wind impacts blunted some in the Big Bend/Panhandle. 

Still a lot of uncertainty for something less than 72 hours out. 

[NorthHillsWx]

I haven’t posted in a little while and have been watching this storm develop but have a couple of things to say:

1) models (GFS guilty as charged) have proven to show their bias in developing these CAG systems too quickly. Clearly it’s taking this time to organize, and imo that was expected and models showing this jumping straight to a hurricane were out to lunch 

2) the development signal overall track guidance has been EXCELLENT. I mean it’s been DAYS and the general idea of development and movement haven’t changed and that’s before we even have a named system 

3) intensity forecast is… problematic at best. The ULL to the west and a trough interaction on approach are significant variables that are difficult to forecast. If aligned improperly, both features could impart shear on the system both as it develops and also as it heads towards the coast. However, as the ULL retrogrades NW, it could leave a window with an extremely favorable environment and explosive SST. Models are extremely split on how this interaction plays out.
 

4) I would not take eastern tracks off the table quite yet. The ULL I spoke to earlier is what pulls this westward. The further east this forms, the less of an influence that system will have. Ian is an example where models greatly overestimated the interaction with a ULL in the western GOM and yea, let’s just say those track forecasts were way off. That being said, guidance is extremely and I mean extremely clustered for there being a COC. I guess this is just directed to say not to let your guard down across the entire west coast of Florida.

 

5) Stop the hype. This isn’t pointed at this forum, but the hype level this storm has received is off the charts. I’ve seen extremely tempered weather folks on social media throwing out HAFS runs showing a 888 catastrophe for Florida while failing to post the 975 cat 1/2 from the next run. Extremely respected Mets seemingly have slurped the kool aid on this one and I can tell you it’s unlike any storm I’ve ever seen before from a social media perspective, considering it’s not even a tangible named system yet.

[StantonParkHoya]

[Floydbuster]

I got the sense from the NHC discussion that they don't seem very impressed with the system tonight. The discussion to me read rather "meh". Surprising, given the likelihood of a major hurricane landfall. Perhaps I'm reading too much into it (literally).

[NorthHillsWx]

1 minute ago, Floydbuster said:

I got the sense from the NHC discussion that they don't seem very impressed with the system tonight. The discussion to me read rather "meh". Surprising, given the likelihood of a major hurricane landfall. Perhaps I'm reading too much into it (literally).

I do think they probably saw the current state and models trending downward as maybe signs to be slightly less bullish at this time but I literally thought the exact same thing when I read it. IMO the forecast makes sense. There’s no reason to change anything from their track or intensity forecast at this time. 

[SnowGoose69]

The NAM agreeing with the current 00Z hurricane models would be the best NAM/ETA hurricane track forecast in history at 72-84 if it verified

[MattPetrulli]

3 minutes ago, NorthHillsWx said:

I do think they probably saw the current state and models trending downward as maybe signs to be slightly less bullish at this time but I literally thought the exact same thing when I read it. IMO the forecast makes sense. There’s no reason to change anything from their track or intensity forecast at this time. 

Still forecasts a major at LF

 The official intensity forecast is similar to the previous 
one and lies between the statistical-dynamical model guidance and 
the purely dynamical model predictions.  It should be noted that 
the 72-hour forecast allows for a little weakening after moving 
inland, so the cyclone is still expected to be at major hurricane 
strength at landfall. 

[RU848789]

1 hour ago, wthrmn654 said:

Lol, did the uk go due north at 18z?

I wish these model plots would include the Rosetta Stone translator for the model names relative to their common names, lol...

[CTWeatherFreak]

18 minutes ago, MattPetrulli said:

Still forecasts a major at LF

 The official intensity forecast is similar to the previous 
one and lies between the statistical-dynamical model guidance and 
the purely dynamical model predictions.  It should be noted that 
the 72-hour forecast allows for a little weakening after moving 
inland, so the cyclone is still expected to be at major hurricane 
strength at landfall. 

The cone no longer has it as a Major at landfall.

[MUWX]

2 minutes ago, CTWeatherFreak said:

The cone no longer has it as a Major at landfall.

Thats not how the cone works 

[AccuChris]

Looks like perhaps a CDO is developing overtop the low level center. See how this evolves and persists overnight but this may be the beginning stages of this thing for real


.

[CTWeatherFreak]

3 minutes ago, MUWX said:

Thats not how the cone works 

Look at the cone depiction from 8pm. Its marked as an M at landfall..  On the latest, it shows H at landfall

[MUWX]

1 minute ago, CTWeatherFreak said:

Look at the cone depiction from 8pm. Its marked as an M at landfall..  On the latest, its not.

Because the expect it to make landfall before 8:00. The advisory says the still expect landfall as a major, it will just be slightly inland and weakening at 8:00 now. 

[NorthHillsWx]

Just now, CTWeatherFreak said:

Look at the cone depiction from 8pm. Its marked as an M at landfall..  On the latest, its not.

They explicitly say it’s forecast to be a major at LF in the discussion. The only change between 5 pm and 11 was guidance has trended down as a whole. I’m taking all intensity guidance with a dump truck worth of salt grains until we get a center. And models initialize correctly. 

[Amped]

No sign of a center on radar. Things can change fast though. Hopefully the 18z euro intensity isn't accurate.

[Regan]

Yeah it’s already being taken less seriously online. They too are seeing the H and questioning the seriousness. They aren’t reading the discussion. At least one media guy has latched on to this too. 

[Floydbuster]

 

[StantonParkHoya]

0z GFS a little quicker and a little weaker. Maybe cat 2 at landfall.

[WxWatcher007]

A couple things also stand out on that GFS run. The first is the presence of a pretty significant Predecessor Rain Event (PRE) in north GA/eastern TN/western NC. 

The second is a significant wind field of TS winds, even along the southeast coast. That kind of onshore flow could cause some flooding issues as well. 

[NorthHillsWx]

Precursor rain event is not ideal. 3-6+ before the storm gets there for some of the mountain areas

[wncsnow]

4 minutes ago, NorthHillsWx said:

Precursor rain event is not ideal. 3-6+ before the storm gets there for some of the mountain areas

I have noticed this for the last day or 2. The Canadian shows something even more drastic with the PRE and hurricane combo. 

[Radtechwxman]

Massive convective blob going up and sustaining near the LLC

[wncsnow]

UK is west of 12Z 

[Windspeed]

Evident on radar out of the Caymans that the recent deep convective bursting is rotating upshear and a noticeable tighter vortmax is now organizing. TCG appears imminent.

[Radtechwxman]

7 minutes ago, Windspeed said:

Evident on radar out of the Caymans that the recent deep convective bursting is rotating upshear and a noticeable tighter vortmax is now organizing. TCG appears imminent.

Agreed. I think we may finally see a TD or more likely a TS evolve. Now big question is how long before RI starts? If it starts sooner given conditions ahead could definitely overachieve. 

[Normandy]

9 minutes ago, Windspeed said:

Evident on radar out of the Caymans that the recent deep convective bursting is rotating upshear and a noticeable tighter vortmax is now organizing. TCG appears imminent.

Indeed that is the meso that makes this Helene.  And with what hurricane John has done I am going extremely high for intensity.  Cat 4 still just north of Tampa is my call