ATL: ELSA - Post-Tropical - Discussion

[eastcoastFL]

ELSA NOW OVER THE FLORIDA STRAITS...
...CONDITIONS BEGINNING TO DETERIORATE ACROSS THE FLORIDA KEYS...


SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...23.9N 82.3W
ABOUT 50 MI...80 KM N OF HAVANA CUBA
ABOUT 60 MI...95 KM SSW OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES

[eastcoastFL]

At 200 AM EDT (0600 UTC), the center of Tropical Storm Elsa was
located by radar from Key West, Florida near latitude 23.9 North,
longitude 82.3 West. Elsa is moving toward the north-northwest near
12 mph (19 km/h), and this general motion is expected to continue
this morning, followed by a turn toward the north by tonight. A
north-northeastward motion is expected on Wednesday. On the
forecast track, Elsa will pass near the Florida Keys this morning,
and move near or over portions of the west coast of Florida later
today and continuing into Wednesday.

Satellite data and NOAA Doppler weather radar in Key West indicate
that maximum sustained winds are near 60 mph (95 km/h) with higher
gusts. Some additional strengthening is forecast through tonight
before Elsa moves inland over Florida.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center. A wind gust of 46 mph (74 km/h) was recently
measured at the Key West International Airport.

The estimated minimum central pressure is 1007 mb (29.74 inches).

[eastcoastFL]

STORM SURGE: A storm surge will raise water levels above normal
tide levels by as much as the following amounts in areas of onshore
winds within the Tropical Storm Warning areas...

Southern coast of Cuba...2 to 4 ft

The combination of a storm surge and the tide will cause normally
dry areas near the coast to be flooded by rising waters moving
inland from the shoreline. The water could reach the following
heights above ground somewhere in the indicated areas if the peak
surge occurs at the time of high tide...

Englewood, FL to Aucilla River including Tampa Bay...3 to 5 ft
Bonita Beach, FL to Englewood, FL including Charlotte Harbor...2 to
4 ft
Aucilla River to Ochlockonee River...2 to 4 ft
Flamingo, FL to Bonita Beach, FL...1 to 3 ft
Craig Key, FL to Dry Tortugas...1 to 2 ft
Ochlockonee River to Indian Pass...1 to 2 ft

Surge-related flooding depends on the relative timing of the surge
and the tidal cycle, and can vary greatly over short distances. For
information specific to your area, please see products issued by
your local National Weather Service forecast office.

RAINFALL: Across portions of Cuba through this morning, rainfall of
5 to 10 inches with isolated maximum amounts of 15 inches is
expected. This will result in significant flash flooding and
mudslides. Across the Cayman Islands this morning, additional
rainfall of 1 to 3 inches with storm total rainfall to 5 inches is
expected. This rain may lead to scattered flash flooding.

Elsa is expected to produce the following rainfall amounts and
impacts this week:

Across the Florida Keys into southwest and western portions of the
Florida Peninsula...3 to 5 inches with localized maximum totals up
to 8 inches through Wednesday, which may result in considerable
flash and urban flooding, along with minor to isolated moderate
river flooding.

Across the rest of Florida into southeast Georgia and the Low
Country of South Carolina...2 to 4 inches with localized maximum
totals up to 6 inches through Wednesday night, which may result in
isolated flash, urban, and minor river flooding.

[AtlanticWind]

https://www.sfwmd.gov/weather-radar/cur ... llite-loop

This is getting sheared pretty strongly now.

Is pulling convection to the northeast
May cause some reformations to the east.

[Jr0d]

https://cdn.discordapp.com/attachments/858799719634829372/861836494946435082/unknown.png
43kt sustained gusting to 53kt now. Anemometer at around 15m.

31mph, gusting to 46mph is the latest from Key West Airport...and we still have much heavier stuff to.come.

Keys Energy was nice enough to text me saying that power outages are expected

Power outages is no fun, hopefully it won’t be out for long. Is surge a concern? I see Satan shoal reporting some big waves.

My generator works just fine, if needed. Surge is an issue for low lying areas and my boat at Garrison Bight marina.

My car is parked at the high school with hundreds of neighbors who took similar precautions. I will check on my boat if it gets really nasty but am well protected at my slip....i took surge into consideration when i added extra lines to the dock.

[JaxGator]

This guy from Key West has been gotten some video of Elsa's effects on the island so far. I don't know how to embed the link, but good ol' copy and paste should do it.

Joel Franco
@OfficialJoelF
A few blocks from the Southernmost Point #KeyWest #Elsa

Joel Franco
@OfficialJoelF
·
5m
Wind check #Elsa #KeyWest


Joel Franco
@OfficialJoelF
Waves getting nasty #Elsa #KeyWest

[ConvergenceZone]

https://www.sfwmd.gov/weather-radar/current-weather-conditions/florida-radar-and-satellite-loop

This is getting sheared pretty strongly now.

Is pulling convection to the northeast
May cause some reformations to the east.

I agree, and I actually think the strength will be less than forecasted. I'm thinking a 45 mph to 50 mph tropical storm at landfall.... If it still looks terrible tomorrow morning, I would say that's a good bet since the shear is only going to increase...

[SFLcane]

Let’s hope this future radar is wrong. But being so sheared it would not surprise me

[AveryTheComrade]

The center is much more obscure on radar than it has been for a while

[Jevo]

I figured as much with as unorganized as she is that a lot of the ugly weather in this storm would be training across the Eastern side of the peninsula.

[EquusStorm]

Just can't stay perfectly stacked and well defined at the low levels lol, now the midlevel center to the LLC be like

[Shell Mound]

If this is the case, do you know why the NHC has been maintaining the intensity at 55 kt? I assume that the NHC knows about the influence of the low-level jet...

The term "low-level jet" is slightly misleading as it implies that the process is not related to Elsa. As far as I can tell, this area of higher winds is really caused by the interaction between Elsa's low-pressure center (and its associated wave envelope), the high-pressure thumb ridge to Elsa's north, and the low-level trade wind surge on the back side of Elsa. It's important for the NHC to include these winds as they are associated with Elsa and will travel with it (including onto land) as long as the interaction continues. It's the same reason why some storms out in the MDR will have higher winds than expected based upon their size and pressure - this interaction between the system, its steering patterns, and its zonal flow is what gives rise to these winds as they wouldn't be occurring otherwise. NHC has to acknowledge them as being a part of the storm's windfield for that reason.

Agree, if Elsa wasn't there, then those winds would be a lot lower. However, the plane found those winds outside of squalls, for the most part, making it hard for them to extend down to the surface. It's not likely surface winds were stronger than FL winds there. NHC's 55 kt wind estimate may be possible, but winds are more likely lower (45-50 kts). I tend to use a more likely wind in my advisories rather than the peak possible. Too many complaints about wind forecasts being too high over land. NHC's job is public safety, mine is providing a realistic estimate of what a business will likely experience. I don't have to worry about getting people to evacuate the coast.

Has the NHC stopped assigning maximum sustained winds on the basis of convectively generated observations? Is it now including winds outside thunderstorms?

[USTropics]

Decent convection firing off to the northeast of the LLC, associated with the MLC (can see our naked LLC in this loop):


You can just make this out in the radar loop as well (red is LLC, pink is MLC):


Animated radar loop:


This displacement was forecast by the 00z HWRF:

[AdamFirst]

Tornado warning in effect for Palm Beach and Hendry County on a cell with rotation south of Clewiston. First one of the storm. Should be more today.

[Chemmers]

Looks like the naked centre might be getting bought in under the over shooting tops now

[Shell Mound]

I actually think that Elsa will strengthen more than it has over the past several days, because the low-to-mid-level shear has diminished. Deep-layer shear will be stronger, but the low-to-mid-level vectors will largely be parallel to the deep-layer winds, so this should allow the vortex to deepen at least slightly as it tracks toward the Nature Coast (Big Bend) of Florida. Plenty of sheared systems in the northeastern Gulf of Mexico have managed to become low-end hurricanes: look at Earl (1998) and Hermine (2016), among plenty of others. I could easily see Elsa managing to become a low-end hurricane prior to landfall.

[Vdogg]

Finally found the LLC, very clearly racing away from the mlc to the NNW on true color sat. Now that I've seen that, not sure if it'll have time to align. Shear seems to be doing a number on the western side of the storm.

[robbielyn]

We are now under a hurricane watch!!!

[AJC3]

You can clearly see the eastward displacement of the convection from the LLC if you overlay 3.9UM IR with the Key West radar. Elsa now has 25kt of westerly wind shear punching into it. On the one hand, that will be a serious inhibiting factor for any intensification. On the other, that eastward displacement is going to make for a real mess of heavy rain, and gusty winds/squalls for peninsular Florida, particularly the west coast.

We should see a pretty decent number of tornadoes develop late today and tonight over most of the peninsula.

[Jr0d]

Just had an intense band in Key West...going yo be interesting to see what kind of winds were clocked. Looks like we still have more coming too.