ATL: ELSA - Post-Tropical - Discussion

[SEASON_CANCELED]

Presented without comment:

"The initial intensity is being held at 65 kt just in case convection redevelops
around the ragged eye feature later tonight."

Really curious as to what caused the almost instantaneous collapse right as it was in ramp up mode. Fascinating

I’ve known you since the 90’s, and you already know. Dynogel.

the MacDill AFB Forcefield was turned on

[HurricaneBelle]

Wind has really started to pick up in Safety Harbor, actually hearing it now a bit from within the house. This ain't no hurricane, but it's still a tropical storm.

What's up my Floridabro

Currently chilling with a Florida Man beer and a Publix Sub

So far nothing but rain in Lutz ...about 30 minutes from you.

Not sure where the wind is...or maybe its coming

What's up right now is that my power is flickering so much that my cable box has rebooted about 5 times in the last 20 minutes.

[SEASON_CANCELED]

Wind has really started to pick up in Safety Harbor, actually hearing it now a bit from within the house. This ain't no hurricane, but it's still a tropical storm.

What's up my Floridabro

Currently chilling with a Florida Man beer and a Publix Sub

So far nothing but rain in Lutz ...about 30 minutes from you.

Not sure where the wind is...or maybe its coming

What's up right now is that my power is flickering so much that my cable box has rebooted about 5 times in the last 20 minutes.

Why haven't you gotten a Generac already? You live in florida. Its easily the best $4000 investment of your life. Throw up a 750 gallon propane tank and you got enough power to run everything for 2 weeks.

Learned my lesson after Irma. Was out of power for 4 weeks almost

[TampaCE]

So far here in Shore Acres area of St Pete we have winds but no real rain to speak of. Roads are dry and we still have power. Going to stay up for a few more hours with high tide coming up at 3:30 but hopefully the surge doesn’t materialize like predicted and I can get some sleep tonight.

[USTropics]

https://imagizer.imageshack.com/img922/5662/pXx8Iu.gif

Can someone weigh in on these high streaming clouds fanning out and away from Elsa as the inner convection collapses?

Energy transfer?

Presented without comment:

"The initial intensity is being held at 65 kt just in case convection redevelops
around the ragged eye feature later tonight."

Really curious as to what caused the almost instantaneous collapse right as it was in ramp up mode. Fascinating

Essentially it was a two-pronged attack. Elsa was experiencing SW shear, which consistently displaced the MLC the NE throughout the day, leaving the SW quadrant of Elsa devoid of sustainable convection. 18z HWRF analysis was Elsa at her peak:


However, if we start to look at the RH for 400-700mb, we can begin to see issues. In the image below, the LLC and MLC are the best stacked we've seen Elsa since the storm crossed Barbados. However, tiny cores are susceptible to dry air intrusion, and we can see this has begun:


Shear from the west is starting to drive mid-level dry air into the center of Elsa, in fact RH values directly to the west of the center were at 57% (to the east we had RH values in the 85-90% range):


At the same time, Elsa is ramping up, her tiny core is finally vertically stacked and the wind field begins to expand. There is no sustained convection on the western/southwestern quadrant of Elsa, and this eventually entrains dry air in the vertical air column of Elsa's circulation. This disrupts vorticity, and Elsa responds by becoming elongated from the east to west (essentially the LLC has become squashed and elongated). At the same time, the MLC becomes decoupled and races off to the NE, away from the LLC. We can see this in the 00z HWRF forecast (8PM ET):


We can begin to see this occur in the last frames of visible imagery, as the outflow boundaries creates a fanning of the cloud tops to the north and northwest:


Here are the last 130 radar frames saved as a video to see this occur in real-time:
[youtube]https://youtu.be/kSzM0Q3zH1Y[/youtube]

[psyclone]

I am getting no rain at the moment but surprisingly strong winds. It's like a classic Halloween gale out there with low clouds racing by. nice for a storm walk.

[USTropics]

This likely has some implications on track as well. A stronger system with a stacked MLC in the 990-1000mb pressure range would have a bit more of a northerly track component, as analyzed in steering flow:


However, with Elsa now being decoupled, we are dealing with a system in the 1000-1010mb pressure range. With Elsa now imbedded in a weaker, low-level steering flow this should carry the system slightly more towards the west (along the western periphery of the NHC track):


This doesn't have much implications for severe conditions, as the convection will remain NE oriented away from the center. This does give Elsa a bit more time over water though, as the GFS has landfall around 18z tomorrow (1PM ET):

[caneman]

Presented without comment:

"The initial intensity is being held at 65 kt just in case convection redevelops
around the ragged eye feature later tonight."

Really curious as to what caused the almost instantaneous collapse right as it was in ramp up mode. Fascinating

I’ve known you since the 90’s, and you already know. Dynogel.

I remember those days and conversation s Steve. Does make you wonder. The good old CFHC days. We had some characters. Remember RobbieLynn. Can't remember all the names. Think MWatkins was there. Hope you are well my friend.

[galaxy401]

Well now it's "officially" downgraded again. Still trudging slightly NNW too.

[Sciencerocks]

[Shell Mound]

Elsa looks to be dissipating just offshore of the west-central coast of Florida. Strong shear and dry air have prevailed, the LLC is exposed, and convection is waning.

[SEASON_CANCELED]

She is done...time is up to become anything significant.

hopefully everyone got through this unscathed

looking more like a weak TS or a Tropical Depression right now

[NXStumpy_Robothing]

Well, I decided to check in on Elsa right before I needed to catch some sleep, and I find myself a bit surprised - compared to earlier tonight (after the core collapse), the storm is looking better.

Her radar appearance has improved, deep convection has refired near or over the northern edge of the center, and inflow has increased substantially on the southern side. Said inflow has even resulted in a massive, lightning-filled rain band with deep convection to develop near Port Charlotte and Fort Myers/Cape Coral, as well as given rise to tornadic couplets in certain spots on the Florida peninsula.

While I'm certainly not anticipating anything as dramatic as what happened in the evening hours yesterday, don't be surprised if Elsa puts on one last semi-impressive display before moving onshore later this morning. Where the storm makes landfall, at what intensity it does so, and what track is taken will be important for future intensity; with the NNW motion tonight, however, there's little chance she manages to cut across to exit offshore prior to the Outer Banks. Hopefully, that limits the system's impact on the already-saturated soils that exist across the Atlantic Coastal Plain.

Most recent radar image (courtesy of Mark Nissenbaum):

IR Satellite Imagery Loop (courtesy of the College of DuPage):

[wxhorse]

Well, I decided to check in on Elsa right before I needed to catch some sleep, and I find myself a bit surprised - compared to earlier tonight (after the core collapse), the storm is looking better.

Her radar appearance has improved, deep convection has refired near or over the northern edge of the center, and inflow has increased substantially on the southern side. Said inflow has even resulted in a massive, lightning-filled rain band with deep convection to develop near Port Charlotte and Fort Myers/Cape Coral, as well as given rise to tornadic couplets in certain spots on the Florida peninsula.

While I'm certainly not anticipating anything as dramatic as what happened in the evening hours yesterday, don't be surprised if Elsa puts on one last semi-impressive display before moving onshore later this morning. Where the storm makes landfall, at what intensity it does so, and what track is taken will be important for future intensity; with the NNW motion tonight, however, there's little chance she manages to cut across to exit offshore prior to the Outer Banks. Hopefully, that limits the system's impact on the already-saturated soils that exist across the Atlantic Coastal Plain.

Most recent radar image (courtesy of Mark Nissenbaum): https://i.imgur.com/7dhtR6J.png

IR Satellite Imagery Loop (courtesy of the College of DuPage):
https://imgur.com/airGbLO

Yep. We were woken up by a tornado warning around 4 am. Just ended. We are getting light winds and lots of rain.

[kevin]

Looks like there's a strong rainband over the Fort Myers region at the moment.

[AveryTheComrade]

50-55kt radar velocities with convection blowing up over the center again, the storm refuses to die

[wxman57]

This storm is not carrying winds aloft to the surface. Should never have been upgraded. Not even a tropical storm-force sustained wind across the Tampa Bay area. Max winds peaked at around 50-55 kts yesterday at its peak.

[rigbyrigz]

Heavy squally rain has started here in Big Bend. Reading all the "downgrade" stuff makes me wonder how the 2PM forecast for nearby Keaton Beach says this as of 6AM:



Even inland Perry shows several hours this afternoon of sustained 50-60- and gusts over 100. Just doesn't jive. (And hope its wrong.)

[AlphaToOmega]

Elsa will be kept as a hurricane (at least in the Caribbean). Its peak intensity is 75 knots. Because the NHC at most changes a storm's peak intensity by 5 knots, a 5 knot downgrade would yield a 70 knot storm, which would be a hurricane. It might be downgraded in the Gulf of Mexico, for its operational peak intensity there was 65 knots.

[Dean4Storms]

This storm is not carrying winds aloft to the surface. Should never have been upgraded. Not even a tropical storm-force sustained wind across the Tampa Bay area. Max winds peaked at around 50-55 kts yesterday at its peak.

Even the best buoy wind measured was only 48.6kts sustained and gust to 68kts. Don't know if it was ever more than 60mph TS.