ATL: IRMA - Post-Tropical - Discussion

[KBBOCA]

 https://twitter.com/philklotzbach/status/906268399918911488

[BYG Jacob]

When's the last time the U.S. had a cat 5 landfall? Most weaken before they hit.

Hurricane Andrew

Camille and Labor Day are the only other hurricanes that have made landfall on CONUS as a cat 5

[fci]

Question - with an Eye wall of approximately 50 miles and full force hurricane winds extending out 20 miles what's the swath of the wind field? 50+20+20 = 90 miles wide??

Per latest NHC update: "Hurricane-force winds extend outward up to 70 miles (110 km) from the center and tropical-storm-force winds extend outward up to 185
miles (295 km)."

When they extend outward to 70 miles, that can be in all directions which would make the swath "up to" 140 miles. But I don't think that they are wholly symmetrical so a key word is "up to".
Can be confusing, I thought it was a great question and I hope that I am explaining it correctly. If I'm not anyone more knowledgeable can chime in!

[tolakram]

You all know the cone right? The track can still shift back and forth so please be vigilant.

[KBBOCA]

 https://twitter.com/DrRickKnabb/status/906269722550968324

[galaxy401]

From what I can gather with recon, there does not mean to be a double wind maximum anymore.

[ROCK]

yeah the west movement has stopped to me and I suspect the models were picking up on this jog and shifted west to compensate. Would not be surprised if they swung a tad east now on tonight's runs with Gonzo flying. Personally, until the NWS can pin point an actual track they are going on best guess in winds for Miami. If she does shift east those forecasts will need to be amended to show increased impacts....JMO...

Are you getting a feel for a shift a bit east or is it becoming established that the westward movement has sealed the west movement from today to be firm?

My feel really doesn't count. The NWS NHC is what matters However given I do have an opinion on track..lol I am leaning dead center up the spine of FL...Stormgeo track similar...and yes slowing down due to reaching the end of the ridge...NW then N movement upcoming sooner rather than later..JMO..personally all of FL is about to be decimated and parts uninhabitable...JMHO..

[bjackrian]

Looks like a drop to 923 mb if I'm reading the HDOB correctly:

211200 2212N 07646W 6961 02515 9238 +203 +117 052047 051 045 002 00
211230 2210N 07645W 6951 02522 9231 +203 +111 047034 038 035 002 00
211300 2209N 07643W 6949 02519 9226 +202 +112 041019 024 022 001 00
211330 2207N 07642W 6957 02508 9229 +193 +140 037006 009 014 001 03
211400 2206N 07640W 6963 02507 9236 +190 +160 239008 013 010 002 00

Edited: And with some surface wind. I'm not sure of the correction factor for surface winds.

Drop of 4 mb's. You wonder, knowing this storm's history. It hasn't been below 155mph for days now! What if it cycled down just a little bit lately, they all do (but this storm's cyclying down is still 155mph). And now after a little breather, and more importantly in a different environment (one of the very best in the basin) you have very solid pressure falls over the next 24 hours. I think this is very possible, and that the 160 mph posted by the NHC for the keys might be conservative. We've never really seen a storm like this. This kind of sustained intensity.

That is estimated pressure and usually has a negative bias, drop will probably be 3-4 mb higher

925 mb with 10 kts of wind on the eye drop.

[BYG Jacob]

Thought I saw 144 kt SFMR somewhere in there, may be wrong.

[jasons2k]

I will be driving out to either LaBelle or Immokalee to try and intercept the eye. Wish me luck.

This is not the kind of storm you want to chase. Period.

[stormreader]

You all know the cone right? The track can still shift back and forth so please be vigilant.

West end of cone near Appalachicola now. And just farther north and inland, you see the west veer over the mainland.

[KWT]

Going to be a close call to Cuba, if it does hit Cuba I suspect we will see some weakening onland (not talking massive amounts, but maybe enough to take it down to a low 4/high 3) but there is still a solid 18-24hrs afterwards in some of the most explosive waters in the Atlantic so restrengthening seems quite probable.

Whatever happens this WILL be an exceptional hurricane that is for sure.

[thoughtsinchaos]

Latest Camagüey, Cuba radar appears to show the ERC pretty much finished with the eye now almost completely enclosed in strong convection once more. Interesting that the new eye doesn't seem much bigger than the old inner eye, I suppose from the frictional impacts of Cuba.

[Shell Mound]

When's the last time the U.S. had a cat 5 landfall? Most weaken before they hit.

Andrew. Labor Day (Florida Keys) and Camille are the others.

It is important to note that none of those earlier landfalling Category-5 hurricanes even neared Irma's size. Camille was only marginally larger than Andrew at landfall, and the 1935 hurricane was more compact even than 2004's Charley. Irma is much more similar to 2004's Frances or 1999's Floyd, both of which were of similar size to Irma's while just east of the Bahamas. Of course, Irma is just as or even more intense than those two cyclones ever were. Given the recent completion of the eyewall replacement cycle, the radius of hurricane-force winds is likely to increase even further, especially once the pressure gradient weakens a bit as Irma's north-northwest turn commences. Hurricane-force winds could very well extend almost one hundred miles from the eye, and gale-force winds almost two hundred miles, by the time Irma crosses the middle to lower Keys. Accounting for the girth of the system, even a weaker solution—say, 120 to 125 knots (140 to 145 mph)—in the Keys would bring tremendous storm-surge and wind-related effects over a very broad area, including high tides along both coasts of the mainland, well to the north of the Keys. At this point, the only thing that could result in a weaker strike is Cuba, and only marginally so. The chance of a Category-5 landfall on the Keys and Everglades National Park, and of a upper-end Category-4 impact to the Naples and Marco Island vicinities, is far greater than one would wish it to be.

[stormreader]

Drop of 4 mb's. You wonder, knowing this storm's history. It hasn't been below 155mph for days now! What if it cycled down just a little bit lately, they all do (but this storm's cyclying down is still 155mph). And now after a little breather, and more importantly in a different environment (one of the very best in the basin) you have very solid pressure falls over the next 24 hours. I think this is very possible, and that the 160 mph posted by the NHC for the keys might be conservative. We've never really seen a storm like this. This kind of sustained intensity.

That is estimated pressure and usually has a negative bias, drop will probably be 3-4 mb higher

925 mb with 10 kts of wind on the eye drop.

Small drop 2 mb's. Storm structure seems improved some, core. Tonight is the night to watch for more important pressure falls.

[ROCK]

I will be driving out to either LaBelle or Immokalee to try and intercept the eye. Wish me luck.

This is not the kind of storm you want to chase. Period.

Yeah if you are not a seasoned vet cane chaser I wouldn't chase this one. Start with a cat 1 and work your way up..js

[jasons2k]

I will be driving out to either LaBelle or Immokalee to try and intercept the eye. Wish me luck.

This is not the kind of storm you want to chase. Period.

Yeah if you are not a seasoned vet cane chaser I wouldn't chase this one. Start with a cat 1 and work your way up..js

There are some seasoned chasers in the Keys, and honestly I think they are crazy.

[Sanibel]

My shelter will be in the eye on that NHC track...This is bad because it is almost certain serious damage for houses on Sanibel Island and surge...

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.

[Sciencerocks]

Thought I saw 144 kt SFMR somewhere in there, may be wrong.

That was the earlier flight into the storm this morning.

The highest smrf now is 123 knots.

[KWT]

Models have come into complete agreement, but its worth noting that the angle of approach to S.Florida will only require the smallest of west shifts to keep this in the far east gulf coast till further north. Its not a likely set-up but its probably only going to require an extra 6-9hrs push to the west for that situation to unfold.

Irma also certainly has grown big recently.