ATL: LAURA - Post-Tropical - Discussion

[p1nheadlarry]

Maximum Potential Intensity
https://i.imgur.com/dy5tHjY.png

30C SSTs all the way to the coast is more than enough to maintain its strengthening even if it was to be shallow warm waters, is moving fast enough.

And all those "Marco's cold wake may affect Laura" comments on social media don't look too good right now. The GOM waters are something else.

Yea, sometimes we forget that cold pools are departures from normal, which are still warm enough to support TCs. Also it's important to look at SSH gradient instead of temperature sometimes of these eddies; for example cyclonic eddies raise the thermocline, but displace it downwards as the PV tendency decreases downstream similar to the tropopause in the atmosphere; the reverse is true for anticyclonic eddies.

[Hammy]

Laura's now the first major hurricane of the season

7:00 AM CDT Wed Aug 26
Location: 26.4°N 91.4°W
Moving: NW at 15 mph
Min pressure: 963 mb
Max sustained: 115 mph

[NotoSans]

Intermediate advisory up to 100kt/963mb.

[GCANE]

Successive eye drops from both planes shows relative humidity quickly dropping at 700mb.
Rapid warm core build up / strengthening.

[Buck]

...POTENTIALLY CATASTROPHIC STORM SURGE, EXTREME WINDS, AND FLASH FLOODING EXPECTED ALONG THE NORTHWEST GULF COAST TONIGHT... ...STEPS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION IN THE NEXT FEW HOURS...
7:00 AM CDT Wed Aug 26
Location: 26.4°N 91.4°W
Moving: NW at 15 mph
Min pressure: 963 mb
Max sustained: 115 mph

[jconsor]

Some important clarification and context re: NHC storm surge forecast for Port Arthur/Beaumont area:

 https://twitter.com/yconsor/status/1298588495859130369

[wx98]

Pressure is tanking:

7:00 AM CDT Wed Aug 26
Location: 26.4°N 91.4°W
Moving: NW at 15 mph
Min pressure: 963 mb
Max sustained: 115 mph

[Do_For_Love]

Well when I went to bed last night, Laura was dropping at 2 mb/hr and I extrapolated that out to mean she would be at about 960 mb at the 8 AM advisory. I know it didn't happen in a linear fashion, but it was pretty much on the money. Doesn't make this situation any less horrifying especially with the rapid deepening currently occurring.

FWIW, 2 mb/hr would take her to 2x12=24, 963-24=939 by 8 PM tonight, which doesn't seem too far off from some of the models. Truly a dangerous and soon to be devastating storm.

[Hammy]

Pressure is tanking:

7:00 AM CDT Wed Aug 26
Location: 26.4°N 91.4°W
Moving: NW at 15 mph
Min pressure: 963 mb
Max sustained: 115 mph

That's 3+ mb drop per hour

[USTropics]

Pressure drops using advisories since 4PM yesterday:

Code: Select all

04PM - 990 MB
07PM - 983 MB
10PM - 978 MB
01AM - 978 MB
04AM - 973 MB
07AM - 963 MB

[HurricaneEnzo]

On the slim chance this landfalls as a Cat 5 it would completely obliterate the shortest interval between Cat 5 landfalls on the Lower 48 by about 20 years. While it is probably on the lower end of the probability side of things it doesn't seem out of the realm of possibility. This is 2020 afterall.

[Shell Mound]

 https://twitter.com/AWxNYC/status/1298590629350580226



 https://twitter.com/DanLinden/status/1298590586577051649



 https://twitter.com/RichJonesJax/status/1298590516301516802

[eastcoastFL]

I slept for a few hours and this thing is a beast already

[BRweather]

Looks like we are seeing a north wobble right now.

[GCANE]

On approach.
GFS has 11 knots of shear. Nearly saturated troposphere.
Only thing holding Laura back would be maybe CIN over land since this is at night.
Very likely a high-end cat 4, wide TC with wrapping helicity.
About the worst-case scenario I can think of.
Prayers, thoughts, best wishes to anyone in the path of this beast.

[BensonTCwatcher]

Pressure drops using advisories since 4PM yesterday:

Code: Select all

04PM - 990 MB
07PM - 983 MB
10PM - 978 MB
01AM - 978 MB
04AM - 973 MB
07AM - 963 MB

....that last one there at 10mb in 3 hours.

[Kingarabian]

AVN loop:

[Do_For_Love]

I hope I don't have to eat these words, but I don't think Laura will get to a 5...I still think most likely she will likely make it to 4 and then either maintain that or slightly weaken to a 3. Honestly though, it probably doesn't matter that much in terms of impacts. The area that gets hit is gonna be changed forever as a result.

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

[Kingarabian]

AF plane getting ready for a SW-NE pass as well.

[Shell Mound]

On the slim chance this landfalls as a Cat 5 it would completely obliterate the shortest interval between Cat 5 landfalls on the Lower 48 by about 20 years. While it is probably on the lower end of the probability side of things it doesn't seem out of the realm of possibility. This is 2020 after all.

Actually, at this time I believe Cat-5 status is not only quite feasible, but also doable at the time of landfall, given shear will likely increase only afterward. The ECMWF/GFS are likely overestimating VWS prior to landfall, given that they have been consistently underestimating the meridional ridging. The only thing that could prevent a Cat-5 landfall at this time is the potential for an EWRC, and the current forward speed means an EWRC is less likely to occur in time, given that some models have been too slow with the progression of Laura, which makes sense in light of the stronger-than-expected ridging. (If Laura were to make landfall in LA as a Cat-5, it would be the first such impact on record, given that Camille technically did not make landfall in LA, but remained just offshore near the MS River Delta.)