ATL: HELENE - Post-Tropical - Discussion

[HurricaneBelle]

I in no way meant to imply it would go to Tampa. I also didn't mean east of forecast track, I meant they almost always bend east which is true and not North and West which was in response to another poster thinking it would go due North. Idalia and many other storms have done same. I've lived here since 1976 so I have 1st hand experience on how these storms act in this area.
I still think Cedar Key.

Gotcha, I was too quick to jump in specific to your post which was more nuanced but I had grown tired of all the "it's gonna go east of the forecast track because Charley/Ian" posts without model support (save the occasional ICON run). I've been here since 1976 myself.

[kevin]

A new convective blow-up directly N/NE of the center (19.2N, 83.5W) and pushing west. Might help to fill in some of the sheared western part of NINE.

[xironman]

The two good drops by NOAA shows a WNW track

[aspen]

The two good drops by NOAA shows a WNW track

https://i.imgur.com/IRTlIGl.png

That supports the latest HWRF/HAFS runs, which show the center pivoting to the west for the next day as the system organizes.

[Jr0d]

Except these systems almost always go slight east of track in this area.

Do they really? Everyone loves to cite Charley and Ian but those were two storms 18 years apart (and different cases, Ian's forecast was changed to south of Tampa Bay almost two days ahead of time unlike Charley). In the meantime you've had Hermine, Debby, Eta, Elsa, Idalia and others all track into the Big Bend/Cedar Key area pretty much as forecast without any major east shifts.

By no means am I suggesting anyone in the Tampa Bay area take this lightly and we always should prepare for the worst but the NHC knows what it's doing.

Irma also took a right turn and off the NHC track, hitting Naples instead of further up the coast like it was supposed to. I’ll
Never forget the meteorologist here saying “It happened again. It took an unexpected right turn.”

I know on Hermine, Debby and Idalia they stayed within the cone but they did nudge a little more right than forecast. Not a lot but a little.

Thus I do buy the argument that storms in the eastern gulf coming from the south do tend to get a little bit more of a shove right than they’re forecast to. Doesn’t happen all the time and no one is saying this will but history has said that it does happen and more than just a couple times.

There will be a trough influencing the storm and it is forecast to have a slight east component because of this. Late September trough's tend to be stronger than early August so had Debby had a similar setup I believe it would have more of an east component this time of year.

So many storms take a sharper NE turn in the area, we can not discount this in the days ahead. Just a slight nudge further east could easily bring an extra 8'+ of surge into Tampa Bay.

Until this is a strengthening tropical storm, I do think the models will struggle. For now it does seem to be on the predicted WNW track and should continue that today. Tomorrow is when that trough should start influencing the storm.

[pcolaman]

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.

[DunedinDave]

Do they really? Everyone loves to cite Charley and Ian but those were two storms 18 years apart (and different cases, Ian's forecast was changed to south of Tampa Bay almost two days ahead of time unlike Charley). In the meantime you've had Hermine, Debby, Eta, Elsa, Idalia and others all track into the Big Bend/Cedar Key area pretty much as forecast without any major east shifts.

By no means am I suggesting anyone in the Tampa Bay area take this lightly and we always should prepare for the worst but the NHC knows what it's doing.

Irma also took a right turn and off the NHC track, hitting Naples instead of further up the coast like it was supposed to. I’ll
Never forget the meteorologist here saying “It happened again. It took an unexpected right turn.”

I know on Hermine, Debby and Idalia they stayed within the cone but they did nudge a little more right than forecast. Not a lot but a little.

Thus I do buy the argument that storms in the eastern gulf coming from the south do tend to get a little bit more of a shove right than they’re forecast to. Doesn’t happen all the time and no one is saying this will but history has said that it does happen and more than just a couple times.

There will be a trough influencing the storm and it is forecast to have a slight east component because of this. Late September trough's tend to be stronger than early August so had Debby had a similar setup I believe it would have more of an east component this time of year.

So many storms take a sharper NE turn in the area, we can not discount this in the days ahead. Just a slight nudge further east could easily bring an extra 8'+ of surge into Tampa Bay.

Until this is a strengthening tropical storm, I do think the models will struggle. For now it does seem to be on the predicted WNW track and should continue that today. Tomorrow is when that trough should start influencing the storm.

I mentioned this yesterday but forecasting this storm is like trying to kick a long field goal through moving uprights.

When you have a hurricane that's still struggling to find a center and that's going to turn this many times in a couple of days and you're trying to time it up with incoming troughs, that is really hard to do. It's going WNW today. Then it's going to turn more NNNW and N tomorrow morning. Then tomorrow night it's supposed to turn more NE...but how NE? Is it a sharp NE turn or a more NNE turn? Then as it approaches the Fla west coast it turns a little more northerly again. Where exactly is that? A 3-4 hour delay in the turn of a rapidly moving storm can make all the difference. So I would not be shocked if there are major track changes either east or west today which is unusual this close to landfall.

[ronjon]

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.

[Nederlander]

Definitely will miss Cuba

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

Looking at that image you would think it will go further west or stall with that high pressure sitting over the NE corner of Florida.

That trough draped over the SE conus will take care of that ridge and that is your escape hatch.

[3090]

Definitely will miss Cuba

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

Looking at that image you would think it will go further west or stall with that high pressure sitting over the NE corner of Florida.

That trough draped over the SE conus will take care of that ridge and that is your escape hatch.

Yep! No doubt. Look at how deep that trough will be diving down south and east. Big time dive.

[Jr0d]

I mentioned this yesterday but forecasting this storm is like trying to kick a long field goal through moving uprights.

When you have a hurricane that's still struggling to find a center and that's going to turn this many times in a couple of days and you're trying to time it up with incoming troughs, that is really hard to do. It's going WNW today. Then it's going to turn more NNNW and N tomorrow morning. Then tomorrow night it's supposed to turn more NE...but how NE? Is it a sharp NE turn or a more NNE turn? Then as it approaches the Fla west coast it turns a little more northerly again. Where exactly is that? A 3-4 hour delay in the turn of a rapidly moving storm can make all the difference. So I would not be shocked if there are major track changes either east or west today which is unusual this close to landfall.

With a center still forming, not only are the uprights moving, but the ball will not stay in the same place when you try to kick it.

Once we get well defined center, at least we will have a good starting point.

[3090]

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.

I have said 97 has to shake away from the ULL. Until it gets parallel and or north of the ULL it will struggle big time. Later this evening and tomorrow 97 should come together into a hurricane pretty quickly unless some dry air comes from out of an unexpected area and derails the process. I dont see that happening at all though.

[Frank P]

Have you ever seen this much RECON activity in a system that is not even a depression?

[skillz305]

Any information on the steering patterns and how they are shaping up? I know the importance of them as to where this ends up heading.

[cycloneye]

12z Best Track has no upgrade to TD or TS, but the presure is down to 1000 mbs.

AL, 09, 2024092412, , BEST, 0, 194N, 837W, 30, 1000, DB

[NDG]

The way convection is building closer to the CoC this morning it should become Helene by 11 AM this morning.
You can also see the shear vector starting to change direction on its western quadrant.

[kevin]

12z Best Track has no upgrade to TD or TS, but the presure is down to 1000 mbs.

AL, 09, 2024092412, , BEST, 0, 194N, 837W, 30, 1000, DB

At this point the delayed TD/TS designation might actually give NINE the possibility to compete for some of the Atlantic all-time intensification records. TD to C5 seems like the most realistic one (if NINE reaches that intensity at all). The other Wilma records feel like they're out of reach, what an unbelievable storm that was.

Fastest intensification from a TD to a hurricane = 12 hours (Harvey 1981)
Fastest intensification from a TD to a C5 hurricane = 54 hours (Wilma 2005, Felix 2007)
Fastest intensification from a TS to a C5 hurricane = 24 hours (Wilma 2005)
Maximum pressure drop in 12 hours = 83 mbar (Wilma 2005, 975 mbar -> 892 mbar)
Maximum pressure drop in 24 hours – 97 mbar (Wilma 2005, 979 mbar -> 882 mbar)

[DunedinDave]

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.

[psyclone]

The track has been pretty locked in for several forecast cycles, not much organization overnight...I'm thinking there's not going to be much concern here but I will be interested to see what people are doing. Sunny and mid 90's...I think I'm going to hit the beach and enjoy a last really nice day.

[pcolaman]

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.

Looking at water vapor ,you can see the ULL slowly moving to the west just ahead of the potential storm. I remember a few yrs back where the ULL was always a major player and it was a restricting factor to slow development. Starting to wonder if this is looking like the same set up? Possibly the reason the models have been aggressive but still not producing a decent storm due to not accounting the ULL? Just thoughts that I have seen before.