ATL: LEE - Post-Tropical - Discussion

[RevanTheJedi96]

This is a remarkable peak season system. It's a joy to watch it go crazy while safely offshore.

Practically a dream system to those of us that just want to watch the 'canes blow. Even if it results in a bit less traffic than usual.

Edit: It would be insensitive to forget to mention that I am a bit worried about Atlantic Canada. Esp as the storm continues to nudge S and W of the target track.

I honestly wouldn’t rule out eastern New England yet, the models are adjusting west and as long as that happens eastern New England could get it pretty bad if this keeps adjusting west

Can't really rule out the East Coast above the Carolinas yet tbh but yeah as a Mainer it's weird to have this beast of a storm potentially heading right towards you.

[Sciencerocks]

 https://twitter.com/VortixWx/status/1699980420765364491

[Poonwalker]

Kinda saw this coming. All it was going to take was ideal conditions and the rocket fuel was there. Iam now glad I didn’t buy a condo on the water when I had the chance. Flood insurance has doubled here in Florida in the last couple years. I can’t imagine what will happen if a cat 5 like this hits where I live near the Tampa Bay region. Thank god this one looks to be scooting north of land so far.

[Teban54]

https://twitter.com/VortixWx/status/1699980420765364491

Peak is expected to be at 180mph! That’s the strongest explicit NHC forecast on record!

[Teban54]

New convective burst with -80C pixels showing up. Lee has not done with intensifying yet.

[CrazyC83]

New convective burst with -80C pixels showing up. Lee has not done with intensifying yet.
https://i.postimg.cc/Lsp90CMK/goes16-ir-meso2.gif

That could be what brings it to 155 kt or higher.

[Fancy1002]

Hi, gang. I don't really feel like cleaning any more sidebar from this thread right now, so...

https://i.imgur.com/HIexmDP.jpg

Agreed

[IsabelaWeather]

New convective burst with -80C pixels showing up. Lee has not done with intensifying yet.
https://i.postimg.cc/Lsp90CMK/goes16-ir-meso2.gif

How do you get the 1 minute frames?

[Teban54]

New convective burst with -80C pixels showing up. Lee has not done with intensifying yet.
https://i.postimg.cc/Lsp90CMK/goes16-ir-meso2.gif

How do you get the 1 minute frames?

These are meso floaters that are put in use for storms and other weather systems as needed, but not all storms have them. Currently, GOES-16 has one on Lee and the other on the mid-Atlantic states, while GOES-18 has one on Jova and the other over Texas.

A few websites have the ability to view the meso floaters. I know Tropical Tidbits and RAMMB do.

[Teban54]

Latest center fix has extrap pressure 920.7mb. SE quad has 131 kt FL and 124 kt SFMR.

[RevanTheJedi96]

We are witnessing history, folks. Already close to sub 920 mb

[cheezyWXguy]

Latest center fix has extrap pressure 920.7mb. SE quad has 131 kt FL and 124 kt SFMR.

I think that’s a 5mb drop from the extrapolated pressure on the last pass?

[MarioProtVI]

154 kt FL 158 kt SFMR

[Teban54]

Latest center fix has extrap pressure 920.7mb. SE quad has 131 kt FL and 124 kt SFMR.

I think that’s a 5mb drop from the extrapolated pressure on the last pass?

I think so.

Also, NW quad has 153 kt FL and 158 kt SFMR. Interesting how this quad always reported higher SFMR than FL winds, even though SFMR has supposedly been fixed to improve reliability at high intensities.

[cheezyWXguy]

Latest center fix has extrap pressure 920.7mb. SE quad has 131 kt FL and 124 kt SFMR.

I think that’s a 5mb drop from the extrapolated pressure on the last pass?

I think so.

Also, NW quad has 153 kt FL and 158 kt SFMR. Interesting how this quad always reported higher SFMR than FL winds, even though SFMR has supposedly begun fixed to improve reliability at high intensities.

I wonder if it has to do with the fact that the coldest cloud tops are on the western side, and seem to originate from the nw quad specifically. Maybe that intense convection is increasing the efficiency of mixing down the winds to the surface.

[CrazyC83]

154 kt FL 158 kt SFMR

That would support 145 kt, if not 150 kt.

[Meteorcane]

Can definitely make a good case for 145kts based on a blend of flight lvl and SFMR values (and the fact the pressure has continued to drop since last advisory). I mean you could even make a fringe case for 150kts but I would like to either see flight winds go up another 5-10kts and/or the eyewall dropsonde instantaneous winds be a bit higher (maybe like 145kt surface with 150+kt mean lowest 500m winds).

[CrazyC83]

Can definitely make a good case for 145kts based on a blend of flight lvl and SFMR values (and the fact the pressure has continued to drop since last advisory). I mean you could even make a fringe case for 150kts but I would like to either see flight winds go up another 5-10kts and/or the eyewall dropsonde instantaneous winds be a bit higher (maybe like 145kt surface with 150+kt mean lowest 500m winds).

I agree, although the pressure drop and blending the data makes me lean towards 150 kt.

[Chris90]

Considering that they adjusted the SFMR because of it being frequently higher than flight level in intense hurricanes, and it's still happening now after the adjustment, I think it's time to consider that the 90% rule might be dated methodology. It's my understanding that the strongest winds in a hurricane are located at the top of the boundary layer, which is much closer to the surface than the 10,000ft flight level, I believe it's around 500m above the surface. With strong convection mixing winds to the surface, it doesn't seem unreasonable that they would find stronger winds at the surface than at 10,000ft. Frequent gusts mixing in the boundary layer to the surface are going to result in stronger sustained winds just because of averaging.

Considering the SFMR now giving 158 after giving 157 earlier, and throwing in undersampling, I think Lee is probably at 160kts, especially with flight level coming up to 154kts now. I would say at least 155kts.

[Yellow Evan]

Considering that they adjusted the SFMR because of it being frequently higher than flight level in intense hurricanes, and it's still happening now after the adjustment, I think it's time to consider that the 90% rule might be dated methodology. It's my understanding that the strongest winds in a hurricane are located at the top of the boundary layer, which is much closer to the surface than the 10,000ft flight level, I believe it's around 500m above the surface. With strong convection mixing winds to the surface, it doesn't seem unreasonable that they would find stronger winds at the surface than at 10,000ft. Frequent gusts mixing in the boundary layer to the surface are going to result in stronger sustained winds just because of averaging.

Considering the SFMR now giving 158 after giving 157 earlier, and throwing in undersampling, I think Lee is probably at 160kts, especially with flight level coming up to 154kts now. I would say at least 155kts.

The 90% reduction factor only marginally accounts for undersampling and FL reductions as a whole are very situational in my experience (RIing systems and ERC systems tend to fall on opposite ends of the spectrum here). But the possible high bias of SFMR prevents me from reading into this too much for the time being.