ATL: HELENE - Post-Tropical - Discussion

[redingtonbeach]

5:00 AM official NHC update = nearly identical landfall location, a tick earlier CAT 3 intensity, but the approaching track in the GOM has shifted noticeably more east.

[eastcoastFL]

Over the on the models thread- after a muted 18Z following a nuclear 12Z series of runs, the high res hurricane models are swinging back to significant hurricane mode.

Upper low near the Yucatan that has been shearing PTC9 is backing W, shear should be dropping as modeled.

https://i.giphy.com/media/v1.Y2lkPTc5MGI3NjExNGM1MnVwcXYzMG9zeDF5c2NiZ3ZseHNxZWozY2RiazNoZHhzN2thNCZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/UPNCSoz2xGkhDaLBmv/giphy.gif

It looks like it's going to be tough for the system to split the channel. It might clip the western edge of Cuba.

It’s more likely to hit Cancun or split the channel than Cuba imo

It’s surely possible, the NHC cone covers the entire channel. I just personally think it’s going to be on the eastern edge of the cone at that point. This is my amateur guess.

[Nimbus]

5:00 AM official NHC update = nearly identical landfall location, a tick earlier CAT 3 intensity, but the approaching track in the GOM has shifted noticeably more east.

Longitude 82.4 is about where Idalia passed last year and you remember the roads that were closed with her.
Just a few inches difference in flood height due to an earlier RI makes the difference between carpet and drywall replacement. I doubt you will need to hunker down in the attic with an axe though.

[eastcoastFL]

If I’m looking at and interpreting the WV loop correctly, the source of the shear is an ULL over the Yucatan backing off towards the west, not the outflow from John. Someone correct me if I’m wrong.

You’re correct.

[caneman]

If I’m looking at and interpreting the WV loop correctly, the source of the shear is an ULL over the Yucatan backing off towards the west, not the outflow from John. Someone correct me if I’m wrong.

You’re correct.

My understanding is that one it gets North of the ULL it will then help to enhance it.

[Blown Away]

Geez only 3-4 days out and the lack of a clearly defined LLC leaves just enough track uncertainty for PTC9 to go anywhere from Naples to Panama City. JMHO

[chris_fit]

Recon missing a dataset, but it appears it's north/right of the forecast track in the short term? Blue line is official forecast track.

[xironman]

Geez only 3-4 days out and the lack of a clearly defined LLC leaves just enough track uncertainty for PTC9 to go anywhere from Naples to Panama City. JMHO

The first plane through was not doing a classic survey, once they get a NE to SW run they can nail down the center. But from NOAA mission 4 you can easily see where it is.

[aspen]

Recon missing a dataset, but it appears it's north/right of the forecast track in the short term? Blue line is official forecast track.

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

Of course the one section of data it’s missing is from the exact center lol.

[caneman]

Geez only 3-4 days out and the lack of a clearly defined LLC leaves just enough track uncertainty for PTC9 to go anywhere from Naples to Panama City. JMHO

The first plane through was not doing a classic survey, once they get a NE to SW run they can nail down the center. But from NOAA mission 4 you can easily see where it is.

https://i.imgur.com/a8PKFMl.png

It's nearly a full degree North and slightly east of the 5 am update.

[Nimbus]

Recon missing a dataset, but it appears it's north/right of the forecast track in the short term? Blue line is official forecast track.

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

The retreating upper level low will tend to tug it west a little later in the forecast when its a deeper system but the NNW initial motion does appear to have continued a few hours longer than initially thought(or bothered to be concerned with for Cuba).

[xironman]

Geez only 3-4 days out and the lack of a clearly defined LLC leaves just enough track uncertainty for PTC9 to go anywhere from Naples to Panama City. JMHO

The first plane through was not doing a classic survey, once they get a NE to SW run they can nail down the center. But from NOAA mission 4 you can easily see where it is.

https://i.imgur.com/a8PKFMl.png

It's nearly a full degree North and slightly east of the 5 am update.

It looked like there was a center reformation or it got pulled north by the MLC going on a few hours ago using SWIR

[kevin]

Note that most models nearly bring NINE to Yucatan. So even if NINE is more east/north than forecast I don't think it's that much at risk of hitting Cuba. If anything, it'll allow for an even clearer run through the channel between Yucatan and Cuba.

[caneman]

Note that most models nearly bring NINE to Yucatan. So even if NINE is more east/north than forecast I don't think it's that much at risk of hitting Cuba. If anything, it'll allow for an even clearer run through the channel between Yucatan and Cuba.

Possibly leaning more towards the right side of forecast cone towards landfall putting Cedar Key and possibly down to Cutrus county more at risk and Tampa Bay for even more effects. But these movements can also tend to smooth out over time unless of course this is a true center relocation. It may also mean we now have a fully stacked system.

[eastcoastFL]

PTC9 doesn't yet look structurally impressive but it sure is growing in overall size with quite a bit of deep convection and cold cloud tops to the east of center. I can imagine it will be significantly larger once shear abates, it gets stacked and it fills into the west.

It might not look like much this morning but that can change rapidly in this environment.

[Keldeo1997]

We got 50 kts FL

[cycloneye]

There is the center at AF pass.

[Hypercane_Kyle]

09L is looking better organization this morning. Definitely getting some shear still from the ULL, likely as a result of John. Now that John is weakening and will quickly be out of the picture, I anticipate gradual organization today followed by rapid intensification once it passes Cuba.

[eastcoastFL]

Recon missing a dataset, but it appears it's north/right of the forecast track in the short term? Blue line is official forecast track.

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

Of course the one section of data it’s missing is from the exact center lol.

Do you know if the last ASCAT caught PTC9?

[eastcoastFL]

Note that most models nearly bring NINE to Yucatan. So even if NINE is more east/north than forecast I don't think it's that much at risk of hitting Cuba. If anything, it'll allow for an even clearer run through the channel between Yucatan and Cuba.

It's hard to tell but it appears that it's been east of the track so far. That's why my guess is that it will hug the eastern side of the cone and brush western Cuba. The models will have a better idea once they ingest the data from this mornings flights.