ATL: IDALIA - Post-Tropical - Discussion

[Keldeo1997]

Miss Piggy last reported the eye 12nm wide.
Border line pinhole.
Seeing a large hot tower on the eyewall now.
Pin hole a good possibility

Pinehole? Well theses good and bad with that. Good that it might bring down the Surge+ small windfield. The bad is that explosive intensification might be possible.

[Highteeld]

Velocities in the northern eyewall picking up on radar too.

[Zonacane]

Some remnant dry air

https://i.imgur.com/bfJ0uRj.png

RH values near 100% is the exact opposite of dry air

It's there in the very lowest levels. A high chance that is why winds aren't mixing down efficiently.

RH values in the lowest level look around 90%, again that's not dry.

[PavelGaborik10]

Some remnant dry air

https://i.imgur.com/bfJ0uRj.png

RH values near 100% is the exact opposite of dry air

It's there in the very lowest levels. A high chance that is why winds aren't mixing down efficiently.

The dry air is gone.

[Full8s]

Saved 2 hr radar loop.

https://i.imgur.com/4imV1JN.gif

Looks still moving mostly north

Agreed. Seems to track right maybe a small fraction of a degree. Maybe.

[GCANE]

 https://twitter.com/NWStornado/status/1696681001848885372

[HurricaneBelle]

And there it is...

 https://twitter.com/NWSTampaBay/status/1696681101266464796

[Highteeld]

RH values near 100% is the exact opposite of dry air

It's there in the very lowest levels. A high chance that is why winds aren't mixing down efficiently.

The dry air is gone.

Almost. Dropsonde will show a fully saturated profile when it is. It's not quite there yet. SFC winds will spike when that happens too.

[GCANE]

Miss Piggy last reported the eye 12nm wide.
Border line pinhole.
Seeing a large hot tower on the eyewall now.
Pin hole a good possibility

Pinehole? Well theses good and bad with that. Good that it might bring down the Surge+ small windfield. The bad is that explosive intensification might be possible.

EWRCs occur relatively quickly with pinholes.
May see an EWRC before landfall

[Highteeld]

Impressive pressure drop. Could make a case for 959 to 960 mb.

[zzzh]

Very flat max wind profile

[NDG]

Impressive pressure drop this evening. If it keeps up until landfall low 940s mb at landfall is not out of the question.

[CryHavoc]

I mean, she's certainly strengthening but this is far from the worst case scenario. Eye is still quite ragged and the winds haven't exactly exploded, landfall isn't that far away anymore.

RI has to start somewhere it doesn't fast forward so I'd say 3mb drop in an hour is a good start.

Indeed, however we will have to see if it continues at such a rate over a prolonged period of time, and even then there's no guarantee the winds catch up before landfall.

We're in a 12ish hour window now.

She's already knocking on the door of a Cat 3. With the eyewall closing off, I don't think you can rule out another 20mb drop before landfall, which is less than 2mb/hr and would put it at 940ish around landfall.

[GCANE]

Helicity is strong quite a bit inland.
Good chance that strong band about to come onshore will spark tornadoes.
Some maybe stronger than EF1 and could track for some distance.

[InfernoFlameCat]

https://imagizer.imageshack.com/img922/1669/etRqmB.gif

Tropical storm into the Northern Gulf seems most likely...Probably no more then 50-55 knots.

Aged like milk.
Although I was thinking the same thing.

[PavelGaborik10]

While I'm glad it didn't occur earlier, RI is certainly well underway, my guess is landfall around 120-125 MPH.

[Teban54]

Impressive pressure drop. Could make a case for 959 to 960 mb.

Keep in mind the low pressure bias of the NOAA plane.

[Highteeld]

Dry air shows itself again. May take a couple hours to mix it out.

[Highteeld]

Impressive pressure drop. Could make a case for 959 to 960 mb.

Keep in mind the low pressure bias of the NOAA plane.

Splashed at 962 with 25 knots. Estimate from sonde, not plane.

[Abdullah]

There are roughly 12 hours until landfall, which should occur around 8 AM tomorrow morning, if I'm looking at the NHC map correctly.

This suggests, depending on the rate of pressure drop, Idalia's minimum central pressure is likely to be between 917 mbar and 953 mbar.

953 mbar upon landfall - Avg. pressure drop of 1.0 mb / hr
947 mbar upon landfall - Avg. pressure drop of 1.5 mb / hr
941 mbar upon landfall - Avg. pressure drop of 2.0 mb / hr
935 mbar upon landfall - Avg. pressure drop of 2.5 mb / hr
929 mbar upon landfall - Avg. pressure drop of 3.0 mb / hr
923 mbar upon landfall - Avg. pressure drop of 3.5 mb / hr
917 mbar upon landfall - Avg. pressure drop of 4.0 mb / hr

What range is most typical for these types of systems?