ATL: MARCO - Remnants - Discussion

[SoupBone]

Small storms, like Marco tend to strengthen very rapidly but they weaken just as rapidly when that enhanced outflow from the trof turns into strong wind shear. Unless that shear does its job and starts weakening Marco by tonight/tomorrow morning, we could see a sunrise landfall in SE LA. We've known that a stronger storm goes north, a weaker one goes west to TX (or MX). I'm betting on shear hitting Marco harder than NHC track indicates. It may have only a short life as a hurricane. I'm fine with a LA landfall. Not forecasting that yet, though. Freeport, TX, currently. May not be much of it left by then, though.

How would either scenarios affect Laura's track?

[tolakram]

Nice big image loop with both storms.

https://whirlwind.aos.wisc.edu/~wxp/goes16/vis_sqrt/goes16_gulf.html

[USTropics]

The more eastern position can be directly related to the large upper-level trough over the GOM that is backing out now:


Essentially while the LLC was positioned way to the south yesterday, all of the mid-level moisture was being streamlined towards the NE:


This stretched out and elongated the mid-upper level vorticity from NE to SW last night:


As the trough has been moving out in the last 12-15 hours, this has allowed for the vorticity to coalesce on the northern flank:


Given the trough is lifting out a bit slower then model runs forecasted a few days ago, and coupled with a deeper Marco and a more NE location then forecasted, a quicker and more direct poleward movement wouldn't be shocking before it bends back west later in the track. If you're in Louisiana/Mississippi I would still pay attention to this. NHC may be playing a bit of catch up at 5PM.

[cainjamin]

Recon now reporting a closed eyewall on the last VDM. If Marco is going to intensify further, now is the time.

[GCANE]

Vort intensity of the south end of the Rossby Wave has been dropping all day.
Likely will reduce the shear ahead of the trof and also allow Marco to push more of the shear out of the way.

[MississippiWx]

Recon now reporting a closed eyewall on the last VDM. If Marco is going to intensify further, now is the time.

Good catch.

New overshooting tops are firing up around the mid-level eye. Could be ready to strengthen again.

[GCANE]

Eye has expanded to 10 nm

[GCANE]

Any right shift in the forecast track and Marco tracks over the Loop Current longer.

[tolakram]

606
URNT12 KNHC 221621
VORTEX DATA MESSAGE AL142020
A. 22/15:44:50Z
B. 20.99 deg N 085.33 deg W
C. 850 mb 1391 m
D. 993 mb
E. 195 deg 15 kt
F. CLOSED
G. C10
H. 34 kt
I. 215 deg 3 nm 15:44:00Z
J. 296 deg 33 kt
K. 215 deg 3 nm 15:44:00Z
L. 54 kt
M. 121 deg 4 nm 15:49:00Z
N. 187 deg 67 kt
O. 113 deg 6 nm 15:49:30Z
P. 18 C / 1525 m
Q. 24 C / 1524 m
R. 15 C / NA
S. 12345 / 8
T. 0.02 / 0.5 nm
U. AF309 0514A MARCO OB 26
MAX FL WIND 69 KT 086 / 10 NM 12:46:30Z
;

[Beef Stew]

 https://twitter.com/EricBlake12/status/1297201539380056064




We'll see what Marco can do as his structure continues to improve. Should have a nice little window coming up for continued strengthening.

On another note... what is it with this name and small storms?

[USTropics]

Here is the link to Cuban radar for those that want to follow along:
http://www.insmet.cu/asp/genesis.asp?TB0=PLANTILLAS&TB1=RADAR&TB2=../Radar/00Pinar%20del%20Rio/lbjMAXw01a.gif

[aspen]

SFMR readings were going in and out during that pass, so we didn’t get any peak SFMR measurements, but FL winds were up to 70 kt.

[GCANE]

After all that heavy lifting, Marco could be ready to take a breather.
Looks like he is starting to entrain some stable, low CAPE air from the NE that is over west-end of Cuba.
Past that, in the Straits, CAPE picks up again.
Outflow from Marco and WISHE over the Loop Current should work out that small pocket of stable air during the afternoon.
More moisture should come in this evening from possible thunderstorms that may develop over the Yucatan.
Likely Marco's eye should open up to a more normal cane that won't be so prone to rapid fluctuations.

[wx98]

By that pass a 65-70 mph TS is justified. Haven’t seen anything conclusive for a hurricane yet.

They still didn’t sample the NE quad.

My bad. They went due east and then came back due west.

[shiny-pebble]

Eye becoming visible

[MarioProtVI]

Dropsonde recorded surface wind of 65 kt. Probably would go 60 kt at intermediate based on the blending of FL, SFMR and the dropsonde, then upgrade to a hurricane at 5 if the current trends continue.

[GCANE]

Recon heading back to the barn.
Eye open again to the SE, 8 nm wide
993 mb

[GCANE]

Drop 30, NE of the CoC.
A bit of dry air in the boundary layer.
Not all that bad, should just put a minor dent in Marco for the short term

[aspen]

Eye is being temporarily obscured by an expanding burst of convection, which could help to fully close off the eyewall.

[GCANE]

 https://twitter.com/MikeFischerWx/status/1297220615401807873