ATL: ISAIAS - Post-Tropical - Discussion

[GCANE]

Clear evidence the warm-core remains intact as seen on snow/ice imagery.

[eastcoastFL]

If you don’t believe in the theory that weaker storms go west, well, it’s on clear display right now. I seriously wouldn’t be surprised if the center hits Miami and keeps going inland. I’m curious what the Euro will look like at the top of the hour. My guess is a big west shift.

Euro is oddly east

[ConvergenceZone]

I agree that the NHC is only keeping it a hurricane just so the public doesn't let their guard down, but I personally think its days are numbered, and like others, I believe it's a tropical storm, maybe 60 to 65 mph mph at this time. Hopefully it will be a depression or less by the time it gets to the NC Coastline, and then just be a big rainstorm as it races up northward....There were just too many factors going against it for development. Hot sea temps don't mean anything if you have lots of dry air and shear.....

You can always tell when a storm has a big diminishing thread as the forum posts slow down significantly....And this time it's justified.

[Kat5]

NNW heading imo

[Jr0d]

I'll remind you all that small storms like Isaias can weaken quickly and strengthen just as quickly. Pay attention on the coast of Florida.

This is very true. Storms like Charley and Michael come to mind that ramped up quickly. Things are looking good right now but nobody should be throwing any parties or declaring it dead until it passes their latitude. Crazy things have happened to storms passing the gulf stream in the past.

Amen! I tried my best to stress this very point earlier today in this thread.

I just talked to my mom in Cocoa Beach, Fl. They are boarded up and stocked up, however she said most are not preparing for a storm.

Hopefully the current weakening trend continues or at least holds steady and this will not be an big deal. If Isaias does manage to surprise us, given the lack of preparing by many residents there will likely be major problems.

Despite the current dry air intrusion and the naked LLC, a fully expect a big rebound in convection tonight. Being a small system should help Isaias maximize the gulfstream waters energy, in my opinion.

[GCANE]

Not much of a dry slot left.
Looking better for the development of an anticyclone over this.

[eastcoastFL]

2pm

Data from the reconnaissance aircraft and Doppler radar indicate
that maximum sustained winds have decreased to near 75 mph (120
km/h) with higher gusts. Although Isaias has weakened after passing
over Andros Island, some re-strengthening is expected tonight and
Sunday morning when the cyclone will be moving over the warm waters
of the Straits of Florida and the Gulf Stream. Isaias is forecast to
remain a hurricane through Monday, followed by slow weakening
beginning Monday night or Tuesday.

Hurricane-force winds extend outward up to 25 miles (35 km) from
the center and tropical-storm-force winds extend outward up to 115
miles (185 km). A wind gust to 49 mph (80 km/h) was recently
observed at Nassau, Bahamas. Doppler radar indicates that
tropical-storm-force winds are located just offshore Broward and
Miami-Dade Counties.

The estimated minimum central pressure is 990 mb (29.23 inches).

[wx98]

Uhhh. where's the beef. this thing better bulk up soon or it's gonna look like that powerhouse of a storm (Don 2011). Naked swirl watch.

I remember that one well. Making landfall while people were picnicking on the beach

[fci]

Wow...... LLC is but an entirely naked swirl spinning off the west over the last very few frames. That's the great news. The bad news is "IF" there's any chance of Isaias rebuilding its middle/upper core, that will seemingly occur closer to (or over) coastal Florida then perhaps might have occurred otherwise. Normally I see a stripped LLC pulling away from it's MLC in the deeper tropics and it's "game over". But with great inflow and high octane SST's, could this be different? If we don't soon see some popping convection over or near center over the next few hours, then it's hard for me to assume conditions to redevelop are reasonable beyond that time. One thing i'll never forget is the surprise that caught everyone off guard here in S. Florida back in 2005. In practically 24 hr.'s back on Aug. 24, an unimposing T.D. in the W. Bahamas rapidly organized into Hurricane Katrina and plowed westward (WSW) into S. Florida. Of course, what later occurred up in Louisiana was the latter historic event that finally resulted.

Katrina became a Tropical Storm in the Central Bahamas

[typhoonty]

Steve Mclaughlin on NBC 6 literally posted a tweet and said on air that there is "a 0% chance Isaias makes landfall in Miami Dade or Broward." I'm wondering how, in the Miami market, he doesn't know what the cone means. Ugh.

[StormingB81]

This is very true. Storms like Charley and Michael come to mind that ramped up quickly. Things are looking good right now but nobody should be throwing any parties or declaring it dead until it passes their latitude. Crazy things have happened to storms passing the gulf stream in the past.

Amen! I tried my best to stress this very point earlier today in this thread.

I just talked to my mom in Cocoa Beach, Fl. They are boarded up and stocked up, however she said most are not preparing for a storm.

Hopefully the current weakening trend continues or at least holds steady and this will not be an big deal. If Isaias does manage to surprise us, given the lack of preparing by many residents there will likely be major problems.

Despite the current dry air intrusion and the naked LLC, a fully expect a big rebound in convection tonight. Being a small system should help Isaias maximize the gulfstream waters energy, in my opinion.

I am in Rockledge and besides clearing out my pool deck I didn’t even put up my shutters.

[wx98]

I agree that the NHC is only keeping it a hurricane just so the public doesn't let their guard down, but I personally think its days are numbered, and like others, I believe it's a tropical storm, maybe 60 to 65 mph mph at this time. Hopefully it will be a depression or less by the time it gets to the NC Coastline, and then just be a big rainstorm as it races up northward....There were just too many factors going against it for development. Hot sea temps don't mean anything if you have lots of dry air and shear.....

You can always tell when a storm has a big diminishing thread as the forum posts slow down significantly....And this time it's justified.

I wouldn’t write it off up the Carolina coast just yet. When it gets in the flow of the trough and begins extratropical transition there could definitely be some intensification as we’ve seen many many times over the years.

[NC George]

Not much of a dry slot left.
Looking better for the development of an anticyclone over this.


https://i.imgur.com/AdqdoO2.png

If you follow the line of storms in the GOM/northern Florida, there's a line developing in SC/NC along the exact same boundary (not visible in this view.)

[Raebie]

Wow...... LLC is but an entirely naked swirl spinning off the west over the last very few frames. That's the great news. The bad news is "IF" there's any chance of Isaias rebuilding its middle/upper core, that will seemingly occur closer to (or over) coastal Florida then perhaps might have occurred otherwise. Normally I see a stripped LLC pulling away from it's MLC in the deeper tropics and it's "game over". But with great inflow and high octane SST's, could this be different? If we don't soon see some popping convection over or near center over the next few hours, then it's hard for me to assume conditions to redevelop are reasonable beyond that time. One thing i'll never forget is the surprise that caught everyone off guard here in S. Florida back in 2005. In practically 24 hr.'s back on Aug. 24, an unimposing T.D. in the W. Bahamas rapidly organized into Hurricane Katrina and plowed westward (WSW) into S. Florida. Of course, what later occurred up in Louisiana was the latter historic event that finally resulted.

Katrina became a Tropical Storm in the Central Bahamas

Katrina had a lot more real estate to work with.

[CronkPSU]

NNW heading imo

give you credit for your tenacity with predicting every model moving east and every motion being futher north than what NHC and the rest of the board is seeing

[NDG]

12z Euro still persistent that deep convection will return this evening, then knocked down again and keep pulsating up & down all the way to making landfall in Canaveral tomorrow evening.
Every time that it will fire deep convection it will take a job more to the north and vice versa when convection winds down.

[DestinHurricane]

NNW heading imo

give you credit for your tenacity with predicting every model moving east and every motion being futher north than what NHC and the rest of the board is seeing

Does look like it just made a sharp NNW turn though. It may be just my eyes.

[chaser1]

It really is a bit perplexing when one compared the vertical structure of a well developed hurricane and some random LLC left naked and spit out from under it's well developed mid to upper vertical core structure. This is neither though. I don't know how to categorize this storms present state other then having a tight low to mid level core but so shallow that it is becoming challenged to reach the higher levels of the atmosphere. Yet we have conducive low level conditions (low pressure environment with strong convergence and high octane SST's). Still, I can't think that left in it's current state Isaias would simply unwind over a couple days time. The conundrum is the difference that some explosive convection over center would serve to maintain and quickly rebuild a more resilient and possibly deeper eye wall. Even an increase in convection from resultant outflow boundaries occurring over the very warm waters beyond the core would typically imply increased moisture feed into the core of the storm. It really is quite weird to see this pulsating process constantly change the apparent organization of a hurricane.

This is a tilted storm. LLC and MLC are still linked, with the LLC providing the fuel and the MLC pumping the pressure, but are pushed away from each other by shear. It's not unusual. TS and sometimes even low-end hurricanes can chug along like this indefinitely. If the shear gets strong enough it breaks the link and the MLC flies off, aka "decapitation". Sometimes the LLC then puts up another MLC and sometimes it dies, depending on middle air conditions, I'd think.

Decapitation has most likely occurred. The MLC appears located near 24N & 77W. It continues to spew outflow and might still offer a couple hours of enhanced moist upper air helping to fend off light southerly shear already in place. With the LLC moving rapidly to the west to WNW, re-alignment goes from unlikely to "Elvis has left the building". Odds of a naked LLC to quickly redevelop a mid level core under marginal conditions are small and highly uncommon.

[supercane4867]

lol

 https://twitter.com/nhc_atlantic/status/1289620468752760834

[Steve]

I just won a race at Gulfstream. You can see the heavy rain coming down now. Next band in.