Major Hurricane Irma- STORM MODE

[Damage In Tolland]

 Based on sat and rapid pressure falls.. she's quickly going into beast mode. High end 4/ low 5 at LF. Good luck to Josh and all that decided to stay . Long night ahead 

[jm1220]

I wonder if there's something to the idea of the right side of the hurricane decaying and forcing the track to the right on the FL Gulf Coast. Is that what forced Charley to turn right? Maybe that can be a saving grace for the Tampa area. 

[Hurricane Agnes]

7 minutes ago, OUGrad05 said:

I'm surprised we don' have tor watches up.  Cells starting to pop up over FL and environment is going to become increasingly favorable for tornadoes.  

SPC has had a watch up (and a few warnings here and there including currently).  Here is the watch put up just after noon today - http://www.spc.noaa.gov/products/watch/ww0481.html

 SEL1

   URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 481
   NWS Storm Prediction Center Norman OK
   1210 PM EDT Sat Sep 9 2017

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     southern Florida
     Coastal Waters

   * Effective this Saturday from 1210 PM until Midnight EDT.

   * Primary threats include...
     A few tornadoes possible
     Isolated damaging wind gusts to 70 mph possible

   SUMMARY...As convection within outer bands of approaching Hurricane
   Irma continues to move eastward across south Florida, risk for
   tornadoes will gradually increase through this afternoon and evening
   with embedded/stronger cells.

   The tornado watch area is approximately along and 95 statute miles
   east and west of a line from 80 miles northeast of Fort Myers FL to
   40 miles southeast of Marathon FL. For a complete depiction of the
   watch see the associated watch outline update (WOUS64 KWNS WOU1).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 0.5 inches. Extreme turbulence and surface wind
   gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
   storm motion vector 9045.

   ...Goss

 

[AfewUniversesBelowNormal]

11 minutes ago, CoastalWx said:

19:15-20:15

Now: Convection is firing up nicely near Tampa and on the coast, the track might be further west.

[bobbutts]

Running a little left of the 18z models (I'm estimating the center position using radar)

[taylorsweather]

1 minute ago, jm1220 said:

I wonder if there's something to the idea of the right side of the hurricane decaying and forcing the track to the right on the FL Gulf Coast. Is that what forced Charley to turn right? Maybe that can be a saving grace for the Tampa area. 

I mentioned that this morning.  I believe JB described it as the frictional effects of land on a CCW circulation.  As the eastern portion of the circulation rides over land, the wind field is impacted/perturbed, creating a right tug to the storm.  At least that is what I recall from memory all those years ago.

[CoastalWx]

1 minute ago, StormchaserChuck said:

19:15-20:15

Convection is firing up without problem near Tampa and on the coast, the track might be further west.

I thought you meant something else. Not sure if that means anything, but the euro was near Tampa or just SE by a few.

[Hurricane Agnes]

1 minute ago, OUGrad05 said:

Weird, I must be having browser issues, I'm showing nothing at weather.gov other than hurricane watches.  Going to restart.

I think what happens is that the most severe watches/warnings will overlay the lesser ones.  So with the color coding, the hurricane ones just obliterate the others.

[bdgwx]

The outflow is looking pretty healthy. The west and northwest aren't ideal, but not horrible either. But, that channel to the north is ripping right now. 18Z SHIPS is very pessimistic about RI, but I still expect some gradual deepening. Winds speeds may not respond very fast, but I do think there's a good chance Irma's kinetic energy will continue to increase.

[jbenedet]

1 minute ago, SACRUS said:

 

 Pretty incredible set up here, considering the eyewall is forecasted to track up the west coast, while the wind field is more expansive on the east side, and will have the background flow to accompany it. It truly is a set up for damaging hurricane force winds across the peninsula.

[superjames1992]

16 minutes ago, beanskip said:

Welp, was east through 24, but zigged back West at 30 and 36, vs. 12z. Might even come close to reemerging in the Gulf at 42.

The latest NHC track is concerning for us, too.  I'm trying to decide whether to drive back up to NC before the storm.  I imagine the power outages are going to be horrible if it does cross over us at hurricane strength considering what Hermine did last year.  There are so many mossy oaks in my apartment complex.  My office is closed on Monday as is.

The trend keeps on going west it seems.

Anyways, Tallahassee is now under a Hurricane Warning.

[CoastalWx]

Not sure if that means much, but the OEW, does have some bands spiraling in towards it. I wonder if that means perhaps it takes over during the overnight, as it shows some nice signatures. I know LEK is big on the bands spiraling in towards the main band,

[salbers]

It's west of the official track even now with the radar overlay site: https://www.sfwmd.gov/weather-radar/current-weather-conditions

As we've been saying there may be a bias with sharp turns of major hurricanes happening later than expected. Sometimes it is much later.

[OUGrad05]

Been watching mission 27 pretty closely, frankly winds at the surface are not very high relatively speaking.  If that ERC takes its time it may fail to hit cat 4.  The radar presentation and other imagery though sure makes it look like there's stronger than 93kt surface winds.  

[Random Chaos]

000
URNT12 KWBC 092153
VORTEX DATA MESSAGE  AL112017
A. 09/21:43:21Z
B. 23 deg 19 min N
  080 deg 38 min W
C. 700 mb 2529 m
D. 92 kt
E. 294 deg 16 nm
F. 032 deg 103 kt
G. 297 deg 19 nm
H. 934 mb
I. 13 C / 3060 m
J. 19 C / 3058 m
K. 16 C / NA
L. CLOSED
M. CO12-25
N. 12345 / 7
O. 0.02 / 2 nm
P. NOAA2 2711A IRMA OB 13
MAX FL WIND 103 KT 297 / 19 NM 21:38:50Z
SEC MAX FL WIND 83 KT; BRNG:309 deg RNG:54 nm
CNTR DROPSONDE SFC WIND 145 / 20 KTS

[hlcater]

3 minutes ago, CoastalWx said:

Not sure if that means much, but the OEW, does have some bands spiraling in towards it. I wonder if that means perhaps it takes over during the overnight, as it shows some nice signatures. I know LEK is big on the bands spiraling in towards the main band,

It has also been contracting slowly over the past several hours and is down to ~28nm. This ERC may take less time since the OEW is smaller whearas the previous one 2 days ago had a 40nm wide eye. Should be more efficient in choking out the IEW and absorbing whats left.

[AlaskaETC]

1 minute ago, OUGrad05 said:

Been watching mission 27 pretty closely, frankly winds at the surface are not very high relatively speaking.  If that ERC takes its time it may fail to hit cat 4.  The radar presentation and other imagery though sure makes it look like there's stronger than 93kt surface winds.  

Is it undergoing a ERC? I haven't seen that mentioned today.

[OUGrad05]

1 minute ago, AlaskaETC said:

Is it undergoing a ERC? I haven't seen that mentioned today.

There's been confirmed two wind maxima /concentric eyewalls and its obvious on radar.

[dan11295]

Almost like Irma is still following the coast of Cuba instead of turning NW atm.

[RichardJacks]

Just now, dan11295 said:

Almost like Irma is still following the coast of Cuba instead of turning NW atm.

Yes, looks to be going west of forecast track

[Hoosier]

2 minutes ago, dan11295 said:

Almost like Irma is still following the coast of Cuba instead of turning NW atm.

Agree.  Perhaps a short term wobble.

[Z-Cast]

https://zeryl.github.io/irma.html

Repository of Key West Live Cams.

[bdgwx]

Taking some radar measurements I get 12 nm for the IEW and 27 nm for the OEW. Velocities in the right flank are 95-100 kts. All measurements taken at ~10,000 ft.

[forecasterjack]

Amidst all the horrible destruction, there's some amazing beauty in Hurricane Irma. I would NEVER wish this storm on anyone, but since it's here, might as well enjoy it. 1 minute loop: https://weather.us/satellite/812-w-236-n/satellite-superhd-1min.html#play

[TPAwx]

27 minutes ago, MattPetrulli said:

Likely will see major destruction from wind and surge in a region from Tampa to Naples. Those saying worse case scenario was avoided need to think before talking. This is pretty much worse case. 

This track and projected strength is not a worst case scenario.  It's not, at least as modeled, going to bring a 30 ft surge to Tampa.  That's actually the worst case scenario, if you're intent on being precise.

[hlcater]

One interesting thing I've noticed is that there is an incredibly large windfield, yet really no intense "maximum". The eyewall is not at all well defined in context of the rest of the storm(FL winds are only 30-40mph stronger here) and is wayyyyyy disproportionate to the mid 930s pressure. I have to wonder what effects this will have. Does this speed up the ERC and quickly allow the OEW to develop a speed max and swiftly begin to choke the IEW, since it is not well defined--Or does it slow the process down since it has to build up a new speed max since the core winds arent really very focused and intense?

[Superstorm]

Is she slowing down?


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[wxmx]

10 minutes ago, NWLinnCountyIA said:

It has also been contracting slowly over the past several hours and is down to ~28nm. This ERC may take less time since the OEW is smaller whearas the previous one 2 days ago had a 40nm wide eye. Should be more efficient in choking out the IEW and absorbing whats left.

Agree with this. If it can complete the cycle before shear starts increasing, then we can expect reintensifying (after the temporal weakening) until landfall.

 

What I have noticed is that hurricanes are particularly vulnerable to moderate shear/dry air intrusions during an ERC, more so than while there's a stable eye.

[forecasterjack]

1 minute ago, NWLinnCountyIA said:

One interesting thing I've noticed is that there is an incredibly large windfield, yet really no intense "maximum". The eyewall is not at all well defined in context of the rest of the storm(FL winds are only 30-40mph stronger here) and is wayyyyyy disproportionate to the mid 930s pressure. I have to wonder what effects this will have. Does this speed up the ERC and quickly allow the OEW to develop a speed max and swiftly begin to choke the IEW, since it is not well defined--Or does it slow the process down since it has to build up a new speed max since the core winds arent really very focused and intense?

I would guess slow down wind increase due to inertial stability, but perhaps someone who knows more can confirm that  

[OUGrad05]

1 minute ago, NWLinnCountyIA said:

One interesting thing I've noticed is that there is an incredibly large windfield, yet really no intense "maximum". The eyewall is not at all well defined in context of the rest of the storm(FL winds are only 30-40mph stronger here) and is wayyyyyy disproportionate to the mid 930s pressure. I have to wonder what effects this will have. Does this speed up the ERC and quickly allow the OEW to develop a speed max and swiftly begin to choke the IEW, since it is not well defined--Or does it slow the process down since it has to build up a new speed max since the core winds arent really very focused and intense?

Yeah its really weird, 93kts max surface wind on recon 27.  But the wind field is very very broad.  The pressure gradient is also somewhat high so I would expect higher winds.  There's a clear double max though, so could be ERC related