ATL: LAURA - Post-Tropical - Discussion

[cfisher]

Drop at 700mb showed high relative humidity.
Given the radar image and plateau in FL winds, could be an EWRC.
They are flying at 700mb, 10K ft
EWRC's occur early in RI TCs.

https://i.imgur.com/an9gUW4.png

But I think the inner core winds are about to increase substantially with it now being closed off. Much more angular momentum conserved

[Kingarabian]

This is why we don't question the NHC; they nailed their intensity estimate. Recon's findings, in terms of pressure (both 968.6mb extrapolated from flight level and 969mb from a dropsonde), flight-level winds and SFMR data, support a 969mb, 110mph Category 2 hurricane. I have no doubt it will be much stronger soon enough, now that it's closed off its eye.

I love the NHC but they were far too conservative for Laura's peak intensity up until 24 hours ago IMO. Their current 110mph estimate is spot on of course.

[Kingarabian]

Drop at 700mb showed high relative humidity.
Given the radar image and plateau in FL winds, could be an EWRC.
They are flying at 700mb, 10K ft
EWRC's occur early in RI TCs.

https://i.imgur.com/an9gUW4.png

Will be interesting to see if it's the melding type that doesn't effect intensity and just overall improves the system.

[Jr0d]

We will get real time data on the rate of pressure drop with the next couple of passes. Going off the latest satellite image, it appear the eye wall has closed off. I do not see any indications it has peaked in intensity.

Laura is a little lopsided with more convection on the east side, but I do not think that will hinder any anything throughout the day. ~12 hours before shear is forecast....it is going to be a long 12 hours.

[KWT]

Sometimes RI hurricanes will undergo a rapid EWRC (literally could take 3-6hrs) and then utterly bomb once complete. A couple have even strengthened through EWRC. Given there is a decent ring of convection around the eyewall and there is a representation at FL of a second peak, however weak. So not impossible.

[HurricaneEdouard]

This is why we don't question the NHC; they nailed their intensity estimate. Recon's findings, in terms of pressure (both 968.6mb extrapolated from flight level and 969mb from a dropsonde), flight-level winds and SFMR data, support a 969mb, 110mph Category 2 hurricane. I have no doubt it will be much stronger soon enough, now that it's closed off its eye.

I love the NHC but they were far too conservative for Laura's intensity up until 24 hours ago IMO. Their current 110mph estimate is spot on of course.

Oh, I agree; the models were clearly consolidating around the remarkably consistent HWRF in terms of forecasting a Category 4. Waking up to the forecast of a Category 4 is going to panic some people; would have been better if they called this yesterday or even the day before.

[cfisher]

Looking like an annular hurricane on IR. There's nothing stopping Laura from bottoming out at MPI.

[Kingarabian]

We will get real time data on the pressure drop with the next couple of passes. Going off the latest satellite image, it appear the eye wall has closed off. I do not see any indications it has peaked in intensity.

Laura is a little lopsided with more convection on the east side, but I do not think that will hinder any anything throughout the day. ~12 hours before shear is forecast....it is going to be a long 12 hours.

Still about 24 hours left in open water as well. Still has a lot more strengthening to do unfortunately.

[PavelGaborik10]

Lightning firing in the inner core now. Don't see an ERC happening near-term

There's no time for an EWRC to occur. She literally just finished closing off her eyewall within the past couple of hours.

Derek is wrong here.

That's enough time for an ERC. EPAC systems do this all the time. This is the worst possible time for the system to do an ERC though. Will allow it to expand its wind field and give it enough to recover.

Unless it wants to pull a Bill (08) and self destruct, I don't believe an EWRC is likely. Recon data tends to concur with my assessment.

If it wants to pull an EWRC, it won't complete it .

[Kingarabian]

NOAA plane about to penetrate the eye.

[GCANE]

Recon reported the closed eye to be 25 x 34 nm.
An EWRC would expand this to maybe 70 nm wide.
I shudder to think a Cat 4 with this size making landfall.

[supercane4867]

I would wait until the next microwave pass before calling it an ERC.

[USTropics]

It seems a bit too early for an EWRC starting, however this is behaving more like a WPAC typhoon (limited experience with) so I will default to those guys. The deep convective band associated with the inflow makes it appear that way. Time will tell.

[supercane4867]

As of 07z the eyewall is still yet to be completed. Also the size of the eye needs to contract a good bit from here for an ERC to begin with.

[AveryTheComrade]

As of 07z the eyewall is still yet to be completed. Also the size of the eye needs to contract a good bit from here for an ERC to begin with.

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

there is recon data showing a completed eyewall

[Kingarabian]

SSMI and SSMIS passes on the way. Let's hope they don't miss.

[PavelGaborik10]

Sometimes RI hurricanes will undergo a rapid EWRC (literally could take 3-6hrs) and then utterly bomb once complete. A couple have even strengthened through EWRC. Given there is a decent ring of convection around the eyewall and there is a representation at FL of a second peak, however weak. So not impossible.

Extremely rare in the Atlantic from my experience.

[Kingarabian]

Pressure looks to be 967mb.

[cfisher]

I believe CAPE values are high enough for Laura to maintain an annular structure. She's going to bottom out at MPI

[NotoSans]

NOAA plane is doing non-standard 650mb mission so conversion factor for flight-level winds would be HIGHER than 0.9 (my guess is ~0.92). First pass would be E-W.