ATL: LAURA - Post-Tropical - Discussion

[Brent]

After a westward jog earlier, Laura is estimated to be moving
west-northwestward again or 290/15. The synoptic situation consists
over a large ridge near the southeastern United States and a
weakness in the ridge over Central Texas due to an inverted trough.
Laura should gradually gain latitude and turn to the northwest and
north-northwest over the next two days while it is steered between
those two features, move northward late this week through the
southern United States, then move quickly eastward across the
eastern U.S. over the weekend as it encounters the mid-latitude
westerlies. The majority of the guidance has shifted a notable
distance to the west on this run, perhaps due to a weaker trough
over Texas and a more westward initial position of Laura (possibly
due to persistent northerly mid-level shear). The new NHC
prediction is at the eastern edge of the new guidance envelope since
I don't want to bite off on such a large change on just one set of
model runs. But since the storm has been tracking west of forecast
expectations for quite some time, future westward track adjustments
could be required later today.

[Keldeo1997]

Even the NHC thinks it might be to far East but they don't want to make such a big change that quickly

[Ubuntwo]

Picking up steam as she hits the water.
Convection firing south of the CoC.

Very moist air thru the troposphere.
CAPE = 1725
Shear = 6 knts
Humidity = 89%
TPW = 2.57

https://i.imgur.com/hlS61ii.png

https://i.imgur.com/2UM7hNX.gif

That interpolated position is way off, BTW. 5AM pins center smack dab in the middle of that CDO (22.9N, 85.7W)

[kevin]

First time there's a major hurricane in the NHC forecast.

[Kingarabian]

AMSR2 pass shows the beginning of a cyan ring. Still open to the north though.

[GCANE]

Looks like it will be about 12 knots of shear for the next 18 hrs.
Then drops in 24 hrs and will be essentially zero from 30 hrs to 42 hrs.
Picks up to about 15 knts just before landfall in 54 hrs as it interacts with the Rossby Wave.
355K PV will be in the clear however.
Rossby Wave is not as strong as the previous land-falling TCs.

Will be riding thru essentially saturated air thru the GoM with no dry air entrainment.
NW GoM has a high CAPE pool and Laura will also pick up moisture from the EPAC thru the IoT.
The battle at landfall will be against the relatively weak Rossby Wave and the very-high moisture infeed.

[Keldeo1997]

Eyewall could be closing but its also very far away from the Radar so idk

[hurricaneCW]

Laura really ramping up this morning, intense convection now developing around the center. Could rapidly strengthen later today.

[GCANE]

Big 362 Theta-E Ridge has anchored in the GoM.
Laura tracking into it.

[GCANE]

Anticyclone SW of what GFS is depicting.
So, shear forecast maybe be a bit too high.
Laura could get a bit stronger than current expectations.

[Chemmers]

115 mph at landfall, unfortunately I think that it will only go way up as the days go on

[Kingarabian]

NOAA plane closing in on Laura.

[dantonlsu]

Not liking the shift west in the models & the new forecast, especially parts of the discussion.

Thinking If I'm gonna bug out of Seabrook, will need to be by noon to avoid all the mayham.

[Michele B]

My daughter sent me this as a reminder

Ike
https://uploads.tapatalk-cdn.com/20200825/e0cb9b361b42e4434653a808760e6023.gif


Sent from my iPhone using Tapatalk

Maybe they ought not put the cone out so far when a storm is still so far from landfall.

Maybe only a couple of days out, like indicating a general direction?

The. They can lengthen and “tighten” it up once. It’s more clear where it’s headed?

[Keldeo1997]

Big 362 Theta-E Ridge has anchored in the GoM.
Laura tracking into it.

https://i.imgur.com/ox6v9z9.png

What does it mean?

[GCANE]

6Z GFS is trending for the Rossby Wave to pull north and the Ridge to deepen.
Result is a stronger vort landfalling on the TX/LA Border

[GCANE]

Big 362 Theta-E Ridge has anchored in the GoM.
Laura tracking into it.

https://i.imgur.com/ox6v9z9.png

What does it mean?

Strengthening

[supercane4867]

I'm going with 992mb/60kt for the first recon pass this morning.

[Extratropical94]

I'm going with 992mb/60kt for the first recon pass this morning.

First pass is gonna be NW-SE, so we likely won't see the strongest winds there, but I agree with the intensity estimate.

[GCANE]

That is one strong Ridge and one weak Rossby Wave.
Let's see how they look next couple days.