ATL: FLORENCE - Post-Tropical - Discussion

[Extratropical94]

Center splash dropsonde measures 944 mb with 9 knots, so the pressure is 943-944 mb

[drezee]

Windfield has expanded though...

[CrazyC83]

Given the wind data, I would go with an intensity of 110 kt. Looks like it didn't strengthen despite satellite looking better.

[Bocadude85]

https://i.imgur.com/3DOQVZo.jpg

Florence does love to go south of the forecast track doesn’t she, I’m sure it’s just a slight wobble however

[supercane4867]

It seems that wind field has expanded greatly while the maximum windspeed is reduced. Likely was stronger during daytime today when the eye temp was near 20C. Too bad we didn't have recon at that time.

[Extratropical94]

Also, there is almost no rain in the NE eyewall. Highest rain rates measured are 2mm/hr.

[Sciencerocks]

Also, there is almost no rain in the NE eyewall. Highest rain rates measured are 2mm/hr.

Something is fishy. Project stormfiery 2 is killing the storm as speak.

[PavelGaborik10]

Gotta be honest I expected this thing to take a run at cat 5 tonight. Very surprised by the wind speed.

[tarheelprogrammer]

Hopefully it keeps under performing. Is there anything in its path to keep beating this thing up?

[FLeastcoast]

Also, there is almost no rain in the NE eyewall. Highest rain rates measured are 2mm/hr.

Isn't that the side that usually has the worst rain?

[BobHarlem]

@EricBlake12

Eric Blake Retweeted Philippe Papin

Eyewall replacement cycles- The bane of the TC intensity forecaster. However whatever you trade in the maximum winds, it could be worse because the #hurricane typically grows in size after that. #Florence

 https://twitter.com/EricBlake12/status/1039686070273757185

[Hammy]

Can dry air ingestion initiate an ERC?

[Hypercane_Kyle]

Hopefully it keeps under performing. Is there anything in its path to keep beating this thing up?

Not really, at least in the short term. Some slight mid-level shear right now that's probably causing a little dry air to wrap into the core associated with a dissipating low-level trough off the states, however that will lessen and tomorrow will be prime intensification. Recon continues to support a Cat 4.

[Meteorcane]

Also, there is almost no rain in the NE eyewall. Highest rain rates measured are 2mm/hr.

Although I admittedly am not particularly familiar with the SFMR biases w.r.t rain/rate the lower rainrates (which seem to also correlate with warmer cloud tops and warmer MW brightness temps) would seem to at least partially explain the larger differences between flight-lvl winds and estimated sfc.winds in the NE eyewall.

[Hypercane_Kyle]

Given the wind data, I would go with an intensity of 110 kt. Looks like it didn't strengthen despite satellite looking better.

NHC will probably want to be consistent and give the storm the benefit of the doubt that the recon might not have sampled the absolute strongest winds.

[Sciencerocks]

Can dry air ingestion initiate an ERC?

Yes,

Within my years of watching these I can clearly say without a doubt that dry air causes a unlimited number of these.

Ike 2008
Rita 2005
Frances 2004

For a few examples.

[wx98]

Hopefully it keeps under performing. Is there anything in its path to keep beating this thing up?

Not really, at least in the short term. Some slight mid-level shear right now that's probably causing a little dry air to wrap into the core associated with a dissipating low-level trough off the states, however that will lessen and tomorrow will be prime intensification. Recon continues to support a Cat 4.

Not that pass SFMRs only as high as 105 kt and the reduction from FL only yields about 113 kt.

[Hypercane_Kyle]

I recall Irma last year going through multiple EWRCs in a 24-36 hour period, it's just that Irma was such a monster that it maintained a ridiculous intensity throughout the process.

Hopefully it keeps under performing. Is there anything in its path to keep beating this thing up?

Not really, at least in the short term. Some slight mid-level shear right now that's probably causing a little dry air to wrap into the core associated with a dissipating low-level trough off the states, however that will lessen and tomorrow will be prime intensification. Recon continues to support a Cat 4.

Not that pass SFMRs only as high as 105 kt and the reduction from FL only yields about 113 kt.

... which is Cat 4 intensity.

[psyclone]

With a pressure that low if the max winds have come down the windfield has likely expanded so pick your poison. One way or another there's a price to be paid. I would only take comfort if recon showed a persistent increase in pressure.

[drezee]

Windfield has expanded though...

Do you all realize that recon is showing 80 miles of cat2 flight level winds!!! That is a huge wow from the EWRC...not good for storm surge