ATL: LEE - Post-Tropical - Discussion

[Hurricaneman]

Lee looks so strange on IR. I don't think I've ever seen a hurricane pulse up and down so much over the course of a couple of days. It's like every rotation of the eyewall there's a different amount of convection.

Usually happens with dry air intrusion which seems to be what’s happening here

[Teban54]

Looks like another EWRC?

[RevanTheJedi96]

Looks like another EWRC?
https://i.postimg.cc/1XWpW5nz/goes16-ir-13-L-202309110135.gif

Good, I hope it gets stuck in a permanent EWRC lol

[REDHurricane]

Lee is putting up a really strong fight here regardless of eventual outcome. Kind of inspiring if you think about it

[aspen]

Looks like another EWRC?
https://i.postimg.cc/1XWpW5nz/goes16-ir-13-L-202309110135.gif

Good, I hope it gets stuck in a permanent EWRC lol

That’s what the HAFS-A/B have been showing.

[Teban54]

Looks like another EWRC?
https://i.postimg.cc/1XWpW5nz/goes16-ir-13-L-202309110135.gif

Good, I hope it gets stuck in a permanent EWRC lol

That’s what the HAFS-A/B have been showing.

Another round of hot towers are wrapping around. Doesn't look like EWRC, may just be a pulse down phase.

[TallyTracker]

The NHC said it was likely dry air entrainment. With the current structure of the storm and holes in the eyewall, that is to be expected. The banding is largely a result of the dry air not EWRCs.

[aspen]

There’s a clear double wind maxima in the NW quadrant, but the pressure is still dropping, so I’m not totally sure what’s going on. Down to 944.1mb extrap

[Kazmit]

Min pressure has continued to fall but winds have not caught up.

[Hypercane_Kyle]

Looks like another EWRC?
https://i.postimg.cc/1XWpW5nz/goes16-ir-13-L-202309110135.gif

Good, I hope it gets stuck in a permanent EWRC lol

That's how you become a surge monster.

[abajan]

Min pressure has continued to fall but winds have not caught up.

The winds will not necessarily increase. If the areal coverage of hurricane-force and storm-force winds continues to expand while the maximum sustained winds remain unchanged, Lee is actually getting stronger because it takes more energy to drive those winds over a larger area.

[GCANE]

Eye Shape: Concentric (has an inner and outer eye)
Inner Eye Diameter: 23 nautical miles (26 statute miles)
Outer Eye Diameter: 70 nautical miles (81 statute miles)

[cycloneye]

No change on 12z Best Track.

AL, 13, 2023091112, , BEST, 0, 233N, 632W, 105, 948, HU

[TallyTracker]

Min pressure has continued to fall but winds have not caught up.

The winds will not necessarily increase. If the areal coverage of hurricane-force and storm-force winds continues to expand while the maximum sustained winds remain unchanged, Lee is actually getting stronger because it takes more energy to drive those winds over a larger area.

This could actually be worse than a tight, intense core. Lee will wind down slower over cool waters if it’s more spread out and massive. Also, the odds of having a major impact increases substantially since the storm will cover a vast area. Eastern New England is increasingly likely to have TS impacts and significant surge over a large area early next week. Nova Scotia will get impacted even if the center curves eastward and doesn’t landfall.

[kevin]

Data from the last recon passes. The on average 22 nm RMW results in an undersampling correction factor of 5% for a cat 3.
Based on these passes I'd go with a current intensity of 947 mb and winds of 110 kt. 105 kt is a safe bet, but I'd increase it due to the exceptional eyewall drops.
However, due to Lee's erratic nature and fluctuating intensity I'd understand it if NHC keeps it at 110 kt. The last pass went through the NE and SW part of the eyewall while the N eyewall clearly has the strongest winds based on pass 1 and 2 as well as the eyewall drops so that's why I disregard the 3rd passes' wind measurements for the intensity. It does show how Lee's windfield is still not very symmetrical despite being a MH.

Pass 1
946.7 mb with 32 kt -> 943.5 mb
105 kt SFMR and 106 kt FL -> (106*0.9+105)/2*1.05 = 105 kt
RMW 27 nm

Pass 2
944.1 mb with 6 kt -> 943.5 mb
102 kt SFMR and 106 kt FL -> (106*0.9+102)/2*1.05 = 104 kt
RMW 20 nm

Pass 3
947.7 mb with 5 kt -> 947.2 mb
81 kt SFMR and 101 kt FL -> (101*0.9+81)/2*1.05 = 90 kt
RMW 19 nm

Eyewall drops
Drop 7 -> 09:59z -> 111 kt surface winds
Drop 9 -> 09:59z -> 120 kt surface winds
Slight correction since the eyewall drops can possibly be contaminated with gusts so I estimate winds of 110 - 115 kt.

Eyedrops
949 mb with 11 kt -> 948 mb
948 mb with 2 kt -> 948 mb

[kevin]

Despite sort of looking like it's falling apart, Lee has *finally* entered a region of ~favorable shear (15 kt). Idk how long it'll last though. Only 6 hours ago it was under almost 30 kt of shear. This rapid decrease in shear might also be the reason for some of the weird core behavior by Lee (idk enough about shear to say that with any certainty though). But maybe, just maybe, Lee will intensify later today.

[ElectricStorm]

Looks like it's still struggling with structure/dry air issues. With this structure it's probably not going to get nearly as strong for its second peak as I thought it would, but perhaps it can finally get going later today

[cycloneye]

 https://twitter.com/VortixWx/status/1701228412633833822

[cheezyWXguy]

Lee has clearly been undergoing a grungy ERC since last night and looks to be more or less wrapping it up now. Looks like a huge outer eye while the inner is generally just a cirrus canopy at this point. I doubt there will be much intensification today, it looks like a lot of dry air has been ingested in the process and the pressure gradient has probably flattened, but I guess we’ll see.

[Hurricane2022]

the inner eyewall is almost gone on VIS now.