ATL: HELENE - Post-Tropical - Discussion

[InfernoFlameCat]

Not many hints of banding features or rotation in the wider view infrared. Big system, yes, looks like a healthy TC, not at all. This probably isn't in a hurry to organize.
https://i.giphy.com/media/v1.Y2lkPTc5MGI3NjExZzI5Z3l6azVmNjE4dHkzYmt4NTAzbHRnZXN5dTBseXJ5a21xZnRqMSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/LEaBkR5vuANd0nPYBy/giphy.gif

Where do you see a lack of banding? I see plenty of banding, along with little evidence of shear. It seems to be quite the impressive system so far with banding around the entire system. There is excellent outflow as well. Especially in the northeast quadrant.

[grapealcoholic]

Very little spin in the mid levels. will take some time to get going. A convective burst over center could kick things off

[cainjamin]

I agree, once we get sustained convection over the center I think pressure will start to drop more quickly. I'm interested to see how the next HAFS and HWRF show the core developing, they were pretty good with Francine and Ernesto.

[Frank P]

The big picture.

[Blown Away]

2:00 PM EDT Tue Sep 24
Location: 19.4°N 84.5°W
Moving: WNW at 12 mph
Min pressure: 999 mb
Max sustained: 45 mph

Helene does not look like she is moving WNW at 12 mph, unless that little LLC/eddy is what we are tracking. If yes, it's moving NNW. JMHO

[NDG]

 https://x.com/NDGMETCHEF/status/1838671679280623855

[beachnut]

[url]https://i.postimg.cc/3rfJ3Bt1/43eb7fc7-1cc8-417b-94e0-a4163e9ee43d.gif [/url]

12z GFS had the LLC bounce south then north in the next 18 hours at @85.6. It's occurring now a full degree E at @84.6. Maybe this very small eddy/LLC is rotating around a larger broader circulation, but if this is what the models are tracking it's occurring a full degree east than modeled.

It might not go over the tip there on Western Cuba, but I think it will get close and defy many of the models that show Helene closer to Yucatán or even going over.

Once she fills that naked swirl, it’s off to the races unfortunately.

From a size perspective, this is going to be a big girl, isn't it? Sure has the makings of that. Hopefully it doesn't get to the size that Wilma was. That thing was one of the biggest monsters I ever saw. Gilbert was another. Let's hope we don't see that here.

Anecdotal but I remember Gilbert too. Wife and I drove down from St. Pete down to our favorite inn on Ft. Myers Beach. They would toss a copy of the News Press at your door every morning. The front page pic of the cdo looked like it filled the entire gomex, yet we still had great beach weather, crazy.

[Steve]

I agree, once we get sustained convection over the center I think pressure will start to drop more quickly. I'm interested to see how the next HAFS and HWRF show the core developing, they were pretty good with Francine and Ernesto.

They went from low 900's to mid/upper 900's in a couple of runs. I realize it comes down to different data and potential land interaction and not land interaction. But they're hahaFS-A and B today.

For instance, A gets it down to about 969mb before landfall at 12z, 921mb at 06z and 936 at 00z. B has it at 962mb at 12z, 909mb at 06z and 923mb at 00z. So all over the place based on the circumstances which should be expected since their outputs can be extremely fickle.

[Weatherboy1]

Sooooo it's about 130 miles from the tip of the Yucatan to the tip of Cuba. If Helene doesn't start wobbling/steering W pretty soon, she's going to emerge into the Gulf well EAST of estimated forecast/model points. Small differences now could have big implications later on landfall IMO.

[galaxy401]

Next 24 hours are going to be very interesting. Looks like a storm that will soon be a monster...

Been reading this type of thing for 2-3 days. Eventually it will come true maybe. Hopefully it doesn’t.

Despite some on the contrary, Helene's pressure has been slowly dropping for the last 24 hours. Looks like it's still dropping according to the buoys. Recon will know for sure.

[Zonacane]

Not many hints of banding features or rotation in the wider view infrared. Big system, yes, looks like a healthy TC, not at all. This probably isn't in a hurry to organize.
https://i.giphy.com/media/v1.Y2lkPTc5MGI3NjExZzI5Z3l6azVmNjE4dHkzYmt4NTAzbHRnZXN5dTBseXJ5a21xZnRqMSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/LEaBkR5vuANd0nPYBy/giphy.gif

There is plenty of banding and rotation

[Stormlover70]

The big picture.
https://i.ibb.co/RCkMhKh/bigp.jpg

she is huge just like forecast said she would be.

[Pipelines182]

Not many hints of banding features or rotation in the wider view infrared. Big system, yes, looks like a healthy TC, not at all. This probably isn't in a hurry to organize.
https://i.giphy.com/media/v1.Y2lkPTc5MGI3NjExZzI5Z3l6azVmNjE4dHkzYmt4NTAzbHRnZXN5dTBseXJ5a21xZnRqMSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/LEaBkR5vuANd0nPYBy/giphy.gif

Where do you see a lack of banding? I see plenty of banding, along with little evidence of shear. It seems to be quite the impressive system so far with banding around the entire system. There is excellent outflow as well. Especially in the northeast quadrant.

So convective bands in a tropical system spiral into the center and/or circle the center in a somewhat symmetrical pattern. When banding becomes apparent, you should be able to start placing the approximate center of the storm based on images alone. A good example of banding at this stage of a cyclone is the classic shrimp look, you have one big band that's spiraling into the center of the storm. Mature hurricanes tend to have more of the symmetrical banding features.

While the convection we see with Helene have a curvature to them, they don't spiral into the center at all and there's no symmetry with the center, and you can't pick out the center looking at IR. I could be incorrect, but this doesn't look like banding to me.

Edit: the most recent burst of convection on the NE side of the circulation could be a sign of banding

[ROCK]

some good data SHIPS/ buoy data intel..

https://www.ndbc.noaa.gov/radial_search.php?storm=at4

[Zonacane]

Not many hints of banding features or rotation in the wider view infrared. Big system, yes, looks like a healthy TC, not at all. This probably isn't in a hurry to organize.
https://i.giphy.com/media/v1.Y2lkPTc5MGI3NjExZzI5Z3l6azVmNjE4dHkzYmt4NTAzbHRnZXN5dTBseXJ5a21xZnRqMSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/LEaBkR5vuANd0nPYBy/giphy.gif

Where do you see a lack of banding? I see plenty of banding, along with little evidence of shear. It seems to be quite the impressive system so far with banding around the entire system. There is excellent outflow as well. Especially in the northeast quadrant.

So convective bands in a tropical system spiral into the center and/or circle the center in a somewhat symmetrical pattern. When banding becomes apparent, you should be able to start placing the approximate center of the storm based on images alone. A good example of banding at this stage of a cyclone is the classic shrimp look, you have one big band that's spiraling into the center of the storm. Mature hurricanes tend to have more of the symmetrical banding features.

While the convection we see with Helene have a curvature to them, they don't spiral into the center at all and there's no symmetry with the center, and you can't pick out the center looking at IR. I could be incorrect, but this doesn't look like banding to me.

Edit: the most recent burst of convection on the NE side of the circulation could be a sign of banding

There is banding in all quadrants

[ROCK]

neve heard the 90% percentile is regards to size before from the NHC. That was a new one..

[Travorum]

Data from Buoy 42056 which is just NW of Helene at 19.82 N 84.98 W, pressure down to at least 998.2mb. Wind speed looks to be lacking in the NW quadrant which is only just starting to build convection.

[3090]

It might not go over the tip there on Western Cuba, but I think it will get close and defy many of the models that show Helene closer to Yucatán or even going over.

Once she fills that naked swirl, it’s off to the races unfortunately.

From a size perspective, this is going to be a big girl, isn't it? Sure has the makings of that. Hopefully it doesn't get to the size that Wilma was. That thing was one of the biggest monsters I ever saw. Gilbert was another. Let's hope we don't see that here.

Anecdotal but I remember Gilbert too. Wife and I drove down from St. Pete down to our favorite inn on Ft. Myers Beach. They would toss a copy of the News Press at your door every morning. The front page pic of the cdo looked like it filled the entire gomex, yet we still had great beach weather, crazy.

Hurricane Gilbert truly never filled the entire GOM. The BOC yes as Gilbert made its way to its final destination of the upper Mexican gulf coast. But for certain it was and still is one of the top 5 all time largest hurricanes.

[Powellrm]

FYI. ICON has Helene mostly shooting the gap between Yucatán and Cuba versus the other models. Oh, and ICON has Helene down to 947 just prior to landfall-which I don’t think is a coincidence.

[canes92]

It'll be worse with the rain for north GA, northwest SC and western NC because of the mountains.