ATL: ELSA - Post-Tropical - Discussion

[Sciencerocks]

[Hammy]

Been downloading the radar for the Cayman Islands and sped it up, looks like the center is NW of the convection based on banding flow, which is consistent with the shear increasing.

[AveryTheComrade]

The center is in the blob, but convection isn't really rotating around anything.

What direction is it moving? Still NW or more wnw? I can’t make heads or tails of any of this.

Looks WNW to me

[AtlanticWind]

I think this going to be a real lopsided storm as it moves into the gulf.
I expect all of Florida is going to get a lot of rain.

[Hammy]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

[sikkar]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

Appears to be towards 10 o'clock (NW) of the blob with half of it naked.

[sikkar]

920
WTNT45 KNHC 050832
TCDAT5

Tropical Storm Elsa Discussion Number 20
NWS National Hurricane Center Miami FL AL052021
500 AM EDT Mon Jul 05 2021

Elsa appears to be holding steady in strength while moving just
south of central Cuba. Radar data from Cuba and satellite images
show a persistent area of deep convection over the center and some
banding features, especially on the south side of the circulation.
An ASCAT pass from around 0130Z indicated that Elsa was a compact
system with tropical-storm-force winds mostly confined to a region
within about 60 n mi east of the center. Peak winds in the pass were
around 50 kt in the northeastern quadrant, and given the small size
of the cyclone and somewhat course resolution of the ASCAT data, it
seems very reasonable that Elsa has an initial intensity of around
55 kt. This intensity estimate is also in line with the latest
Dvorak classifications. The NOAA Hurricane Hunters will be
investigating Elsa again shortly, and the data the plane collects
will be valuable in assessing the storm's intensity and wind field.

The tropical storm is moving northwestward at about 12 kt on the
southwestern periphery of a subtropical ridge located over the
central Atlantic. A gradual turn to the north is expected over the
next day or two as Elsa moves in the flow between the ridge and a
mid- to upper-level low over the northern Gulf of Mexico. This
steering pattern should take the core of Elsa across central or
western Cuba later this morning, near the Lower Florida Keys tonight
or early Tuesday, and then along or very near the west coast of
Florida later on Tuesday through early Wednesday. Most of the
models show Elsa moving inland over west-central or northern
Florida, but given the expected parallel motion to the coast, much
of the west coast of the state will likely see impacts from Elsa on
Tuesday and into Wednesday. After Elsa clears Florida, it is
expected to move faster north-northeastward across coastal Georgia
and the Carolinas Wednesday and Thursday before moving over the
western Atlantic. The new track forecast is just a little to the
left of the previous one to be in better agreement with the latest
consensus models.

Given the overall favorable environmental conditions, Elsa could
strengthen a little before it reaches the coast of Cuba later this
morning. Some weakening is expected due to the land interaction
with Cuba, but most of the model guidance suggests that Elsa could
restrengthen slightly before it moves inland over Florida.
Significant strengthening is not anticipated though due to moderate
wind shear. However, it should be noted that given the expected
track, much of the west coast of Florida will be on the east side of
Elsa, which is where the strongest winds, highest surge, and
heaviest rains are expected to be. Gradual weakening is forecast
while Elsa moves across portions of the southeast U.S., but some
restrengthening is possible again when the storm moves over the
western Atlantic. The NHC intensity forecast is a little higher
than the previous one while Elsa is expected to be over the Gulf of
Mexico, and it lies near the high end of the model guidance.


Key Messages:

1. Heavy rain will impact the Cayman Islands and Cuba today
resulting in significant flooding and mudslides over Cuba. As Elsa
approaches the Florida Keys, Florida Peninsula, and coastal Georgia
Monday through Wednesday, heavy rainfall may result in isolated
flash, urban, and minor river flooding. Mid to late week, heavy
rains across coastal South Carolina and North Carolina may result in
isolated flash and urban flooding.

2. Tropical storm conditions and a dangerous storm surge are
expected to continue across portions of central and western Cuba
today. Hurricane conditions are also possible along the south coast
this morning.

3. Tropical storm conditions are expected in portions of the
Florida Keys and southwestern Florida tonight and Tuesday, where a
Tropical Storm Warning is in effect. A Tropical Storm Watch and
a Storm Surge Watch are in effect for much of the west coast of
Florida.

4. There is a risk of tropical storm conditions and storm surge
impacts along the coasts of Georgia and the Carolinas Wednesday and
Thursday.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 21.0N 79.9W 55 KT 65 MPH
12H 05/1800Z 22.2N 81.3W 55 KT 65 MPH...INLAND
24H 06/0600Z 23.9N 82.5W 50 KT 60 MPH...OVER WATER
36H 06/1800Z 25.9N 83.2W 55 KT 65 MPH
48H 07/0600Z 28.0N 83.4W 55 KT 65 MPH
60H 07/1800Z 30.1N 83.0W 45 KT 50 MPH...INLAND
72H 08/0600Z 32.5N 80.9W 35 KT 40 MPH...INLAND
96H 09/0600Z 36.8N 74.3W 40 KT 45 MPH...OVER WATER
120H 10/0600Z 42.0N 64.3W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Cangialosi/Reinhart

[USTropics]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

Yea appears the LLC has peaked out from under the canopy, here is the last 30 frames sped up where you can see the low-level cloud deck vorticity at about 21.3, -80.2:


HWRF sees this as well (highlighted the mid-level circulation with an M):


GFS slows down the LLC this morning along the Cuban coastline, being tugged back towards the MLC to rebuild (a pattern for Elsa so far):

[AtlanticWind]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

Thats not where the NHC is placing the center

[Dean4Storms]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

You’re correct and Elsa is now moving more NW and will be on the coast of Cuba in another hour or two.

[Dean4Storms]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

Thats not where the NHC is placing the center

Yes it is, zoom in and you’ll see a naked swirl now tracking more NW.

[sikkar]

Feels like convection is catching up to the swirl.

[AtlanticWind]

After staring at the satellite loop for almost five minutes I managed to pick out the LLC, it's well defined but west of the convection.

https://i.imgur.com/bkcsF2t.png

Thats not where the NHC is placing the center

Yes it is, zoom in and you’ll see a naked swirl now tracking more NW.

The hurricane center coordinates were at 21n 79.9 west at 5am

[NXStumpy_Robothing]

If that area to the NW is indeed the LLC, it appears that Elsa is once again vertically tilted, meaning that a downshear reformation towards the MLC is likely. However, that's well NW of the NHC 5 am position, so I'm not sure if I'm willing to call it that just yet.

[Dean4Storms]

Thats not where the NHC is placing the center

Yes it is, zoom in and you’ll see a naked swirl now tracking more NW.

The hurricane center coordinates were at 21n 79.9 west at 5am

That’s about dead on an hour or two ago.


It’s moved and now has convection popping right on its SE eyewall. about at 80.5

[Dean4Storms]

Recon will be there soon and confirm it. Convection is just starting to pop around it.

[Dean4Storms]

Starting to see the circulation on Key West radar.

[Jr0d]

Looks like the center is just southwest of the Escrambay mountains...recon will be there shortly tell us for sure.

Perhaps the frictional effects of the mountains helped the convection fire.....just in time to.make landfall.

[SFLcane]

Starting to see the circulation on Key West radar.

Interested to see how much of these rain bands we actually get into. Circulation is still far away.

[Jr0d]

Starting to see the circulation on Key West radar.

Interested to see how much of these rain bands we actually get into. Circulation is still far away.

We had a 2 brief heavy downpours in Key West a few hours ago..

Partly clouds now with some low relatively fast moving cumulus and some cirrocumulus also present. Expecting scattered showers throughout the day...don't expect it to really deteriorate until after midnight.