ATL: IRMA - Post-Tropical - Discussion

[ava_ati]

Yeah, I don't see how she could even become a cat 4 after all this land

All that bathtub water with little to no shear between it and Florida. It will spend as much time over water when it turns as it has over Cuba.

[Jelff]

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FEMA shelter map: https://bit.ly/2gQXuhz

[ronyan]

Yeah, I don't see how she could even become a cat 4 after all this land

Well it's still a cat 4 now and it appears to be pulling away from Cuba somewhat with the latest motion. The core would have to be completely disrupted for it to not be able to regain any strength over the straights/EGOM.

[meriland29]

Yeah, I don't see how she could even become a cat 4 after all this land

All that bathtub water with little to no shear between it and Florida. It will spend as much time over water when it turns as it has over Cuba.

It usually takes a storm longer to strengthen than weaken. It took her over a day to get back to cat 5 status

[meriland29]

[tiger_deF]

Irma appears to have completely lost her eye. She has spent over 12 hours wihin very close proximity to Cuba, is there a chance she can recover?

[Crackbone]

Yeah, I don't see how she could even become a cat 4 after all this land

All that bathtub water with little to no shear between it and Florida. It will spend as much time over water when it turns as it has over Cuba.

It usually takes a storm longer to strengthen than weaken. It took her over a day to get back to cat 5 status

I hope you're right, but these will be some of the most prime conditions Irma will enter over its lifetime. Once it lifts off the coast I expect a quick ramp up all the way into FL. The timing of the pull away from Cuba is key, but if it happens soon, Irma will have 24 hours of bathwater and favorable atmospheric conditions to take off.

[AdamFirst]

I don't fault the media for stressing the importance of this hurricane despite the weakening trend. I unfortunately expect a very large damage path that spreads across the entire state, but with varying degrees of impact.

[GCANE]

Eastern Eyewall still rocking
Near 70 mm/hr rain rate

[ava_ati]

Yeah, I don't see how she could even become a cat 4 after all this land

All that bathtub water with little to no shear between it and Florida. It will spend as much time over water when it turns as it has over Cuba.

It usually takes a storm longer to strengthen than weaken. It took her over a day to get back to cat 5 status

It's a cat 4 right now, the graphic at the top is not accurate

[KWT]

Just one other thing to remember, the waters Irma about to go over managed to turn the Labour day storm from a cat-2/3 to an 890s mb hurricane.

Not saying that will happen of course, but it just needs to be remembered that there is still enough time for Irma to really power up even from a weaker position than it is now. The inner core still doing rather well considering how long it has now spent on the coastline and the coastline soon bends back west thus Irma will likely start to gain some distance from land and thus probably start to strengthen again.

[ronyan]

Irma appears to have completely lost her eye. She has spent over 12 hours wihin very close proximity to Cuba, is there a chance she can recover?

Appears is an important word there, a clouded over eye doesn't mean there is no underlying structure.

[cjrciadt]

FL winds are far lower than the last two days, but the windfield is much larger.

Based on the flight level from recon, hurricane strength winds looks to be around 100 miles to the north northeast. Likely a bit less at the surface, but a decent way to see the wind field expanding.

So I could get Cat 1 or 2 sustained even here in Kissimmee, if it passes right over or even W of Tampa bay!?

[Cee22]

Hello! This is my first post here. I just wanted to thank you for all of your informative posts, I really appreciate them.

That being said, some comments ‘almost’ come off disappointed that the storm might not be a category 5 and as someone riding the storm out in Florida, I respectfully ask you to try and contain that. Thanks.

We’re in Brevard County (Melbourne) and we’re well prepared but I hope it won’t be ‘too’ bad, all things considered. We rode out Andrew in Homestead so it’s not our first rodeo but this is a serious storm no matter where or what strength it hits.

Good luck to everyone riding it out too.

[Steve H.]

Yeah, I don't see how she could even become a cat 4 after all this land

Be careful, she has NOT been over a lot of land. Georges had hit almost every island in the greater Antilles and still maintained major status. The land Irma had encountered is almost nothing compared to many CV storms. First thing, this still is a Cat 4. Secondly, she has been going WNW the whole time she has been on the coast of Cuba. Look at the shape of the island. It runs SE to NW. She will begin heading NW, then NNW soon. The NHC is holding onto the idea that she will encounter shear that will keep her from reaching Cat 5 again. I don't think it will be that disruptive. IMO she will go under a period of IR in about 6 hours.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

[FLeastcoast]

I'm very happy to see the pressure rising. Hopefully she continues to weaken a bit before heading my way. Is the Ocala area at a greater or lesser risk than when the storm was forecast to come up the middle of the state? Could it go far enough west so we don't get strong winds?

I'm here with you.. in the villages... great question.. I am interested in the answer also. Stay safe!

[northjaxpro]

Yeah, I don't see how she could even become a cat 4 after all this land

Be careful, she has NOT been over a lot of land. Georges had hit almost every island in the greater Antilles and still maintained major status. The land Irma had encountered is almost nothing compared to many CV storms. First thing, this still is a Cat 4. Secondly, she has been going WNW the whole time she has been on the coast of Cuba. Look at the shape of the island. It runs SE to NW. She will begin heading NW, then NNW soon. The NHC is holding onto the idea that she will encounter shear that will keep her from reaching Cat 5 again. I don't think it will be that disruptive. IMO she will go under a period of IR in about 6 hours.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

That is an excellent summary Steve!

[GCANE]

Mesoscale Discussion 1631
NWS Storm Prediction Center Norman OK
0748 AM CDT Sat Sep 09 2017

Areas affected...Portions of southeastern FL and Keys

Concerning...Severe potential...Watch possible

Valid 091248Z - 091615Z

Probability of Watch Issuance...40 percent

SUMMARY...The tornado risk, while currently on the marginal side,
will increase throughout the morning and (per the forthcoming SPC
convective outlook) continue to ramp up later today as more of the
favorable sector of Hurricane Irma's envelope spreads across the
region. As the tornado threat gradually grows, a watch may be
needed at some point in the next few hours.

DISCUSSION...As of 12Z, the center of Irma was apparent in Miami and
Key West radar imagery near the northern Cuba coast, south-southeast
of HST. During the next few hours, based on NHC forecast track and
translational speed, the center will move abeam of southeastern FL
and the upper Keys, and the northeastern quadrant of the circulation
envelope will begin to impinge upon southeastern FL. This will
include enlarging, increasingly westward-shifting low-level
hodographs, the enlargement already apparent in radar VWP time
series and comparison of 06Z and 12Z MFL soundings. That trend is
forecast to continue through the remainder of the morning.
Meanwhile, persistent moisture transport will help to maintain the
buoyancy apparent in the MFL sounding, while thetae advection inland
overcomes temporary stabilization from the initial QLCS activity.
The 12Z surface chart showed a well-defined thermal axis north of
the outflow area, from Grand Bahama across Broward and Collier
Counties.

Despite the mostly dense/thick cloud cover, diffuse/gradual diabatic
heating also may contribute to buoyancy inland beginning in another
couple hours. As the combined CAPE/shear parameter space gets more
favorable, the main driver of the threat increasingly will be
convective mode. Outflow-dominant, QLCS-type outer bands now over
portions of Miami-Dade, southern Collier and northern mainland
Monroe counties largely have moved through the Keys and should exit
the discussion area in the next couple hours. Following those, a
mixture of clustered, loosely banded and semi-discrete modes is
apparent in radar imagery upstream across the Straits and Bahamas.
Isolated, weak cyclonic-shear areas already have been apparent in a
few embedded cells, manifesting a marginal but still more-favorable
mesoscale environment. More such cells with stronger horizontal
rotational velocity should appear gradually in the next few hours
with closer approaches to the coast and Keys and increasing
potential for their inland survival, with accompanying threat for a
sporadic tornado or two.

..Edwards.. 09/09/2017

[srainhoutx]

Irma appears to have completely lost her eye. She has spent over 12 hours wihin very close proximity to Cuba, is there a chance she can recover?

The eyewall is completely intact. Key West Radar and RECON verify that.

[xtyphooncyclonex]

Yeah, I don't see how she could even become a cat 4 after all this land

Extremely warm sea surface temperatures and favorable conditions over the Florida Straits may trigger another phase of intensification, possibly rapid. Hence, it would be to no surprise this would become 160-175 mph as it landfalls over Florida. I hope my prediction wouldn't happen, but at this stage it is becoming plausible. I guess consistency is the key, I've mentioned on Sept 3rd this may follow a Donna-like track over Florida despite others calling for a North Carolina landfall and a repeat of Matthew.