Major Hurricane Irma

[RUNNAWAYICEBERG]

Rides up FL coastline, worst case playing out here as its just enuff offshore to maintain strength and pound the coast.

[NJwx85]

Up to 183kts at 0.50 degrees elevation.

[the ghost of leroy]

mods should start a model thread so people who don't want to live and die by each run can follow the actual ongoing stuff

[Hoosier]

No sugarcoating this ECMWF run.  A very damaging hit to Miami.

[jojo762]

Easily worst-case potential track for not just MIA but much of the southeastern coast of FL.

[TPAwx]

This is a pretty concerning Euro run given it's 96 hours out.  Miami get crushed.

[NJwx85]

Hammers Ft. Lauderdale and then the eye passes right over West Palm Beach and heading back offshore

[NJwx85]

Eye close to Melbourne, Cocoa Beach

[Windspeed]

Honestly going to take some legit land interaction or dry air to slow Irma down strength wise significantly imo... because YIKES when it gets to those bath waters in the Bahamas near Florida. 

 

Obviously there could be structural changes. But there is so many days left to go, even if a large ERC takes place, perhaps even a few of these, it could still be a borderline 4/5 as it approaches the southern peninsula. Really pouring over 500mb and 250mb maps to try and see how the upper flow pivots as Irma is turning north. The upper environment isn't 360° of perfection like it is now, but the 200 polar outflow channel is on steroids. Give and take, the environment still looks very supportive of an intense major hurricane as it begins northerly motion. Mid-to-upper doesn't really seem to be conducive for strong negative effects and a weakening core until it would already be well inland over the northern peninsula or at the latitude of Jacksonville. And that will depend on how fast Irma is moving N to NNW and how much continental airmass can be undercut into Irma due to the 500-250mb flow around the upper trough to its west.

 

In short, without significant land interaction, Irma can easily still be a large size Category 4 upon a potential Florida landfall if the track verifies. Perhaps even a 5 depending on its internal structure.

 

[yoda]

120 is just east of Daytona Beach/Jax... eye is offshore

[NJwx85]

Headed for a secondary landfall near the GA/SC border, probably as a cat 3 or high end cat 2, although it's hard to speculate on intensity since Irma has unusually high winds at higher pressures.

Edit: Takes a NNW curve, heading closer to Savannah

[Upper Level LOL]

6 minutes ago, cmasty1978 said:

mods should start a model thread so people who don't want to live and die by each run can follow the actual ongoing stuff

The actual ongoing stuff, like model runs precipitating evacuations...

[donsutherland1]

1 minute ago, Windspeed said:

Obviously there could be structural changes. But there is so many days left to go, even if a large ERC takes place, perhaps even a few of these, it could still be a borderline 4/5 as it approaches the southern peninsula. Really pouring over 500mb and 250mb maps to try and see how the upper flow pivots as Irma is turning north. The upper environment isn't 360° of perfection like it is now, but the 200 polar outflow channel is on steroids. Give and take, the environment still looks very supportive of an intense major hurricane as it begins northerly motion. Mid-to-upper doesn't really seem to be conducive for strong negative effects and a weakening core until it would already be well inland over the northern peninsula or at the latitude of Jacksonville. And that will depend on how fast Irma is moving N to NNW and how much continetal airmass can be undercut into Irma due to the 500-250mb flow around the upper trough to its west.

In short, without significant land interaction, Irma can easily still be a large size Category 4 upon a potential Florida landfall if the track verifies. Perhaps even a 5 depending on its internal structure.

Historic climatology for major hurricanes passing within 100 nautical miles of Irma's recent positions and avoiding landfall on Cuba (as appears increasingly likely with Irma) were typically at Category 4 strength upon Florida landfall. Florida landfall still appears somewhat more likely than not and the 12z ECMWF run hammers home that point. Southern Florida should be preparing for a Category 4 or possibly 5 landfall. Hopefully, Irma will miss to the East, but that's far from assured.

[NJwx85]

Splits the goal posts between Savannah and Charleston, but Charleston would definitely get a good pounding.

[the ghost of leroy]

Just now, Upper Level LOL said:

The actual ongoing stuff, like model runs precipitating evacuations...

i meant the cat 5 that is currently hitting lots of things. evacuations should be discussed elsewhere.  nowcasting v forecasting, etc etc

[WishingForWarmWeather]

Just now, cmasty1978 said:

i meant the cat 5 that is currently hitting lots of things. evacuations should be discussed elsewhere.  nowcasting v forecasting, etc etc

There's a thread for obs/evacuations: https://www.americanwx.com/bb/topic/50241-hurricane-irma-local-impactsevacuations/

[LakeEffectKing]

Just now, NJwx85 said:

Splits the goal posts between Savannah and Charleston, but Charleston would definitely get a good pounding.

Looks right into Savannah...but I have old eyes!!

[NJwx85]

We're inside the Euro's wheelhouse now. In less than six days Irma will be inland, most likely over GA or SC.

It appears that the eye, at least the Western eye will pass very close to Miami, in a possible worse case scenario, however a few miles in either direction can obviously have a tremendous shift.

However...we now have tremendous model agreement with the UKMET/GFS/ECMWF/GGEM all showing Irma very close to the SE FL peninsula on Saturday.

[Buddy1987]

Man, I keep staring at that San Juan radar image loop and that eye is way too close for comfort, along with its trajectory if I am living in San Juan right now. It just refuses to want to move more north and west than progged, imo anyway.

[LSC97wxnut]

9 minutes ago, NJwx85 said:

Up to 183kts at 0.50 degrees elevation.

I wonder what the highest wind speed detected by the newer radars in a tornado?

[NJwx85]

Just now, LakeEffectKing said:

Looks right into Savannah...but I have old eyes!!

It's very close, however I'm assuming that Irma has weakened enough that most of the winds have weakened significantly outside of the RFQ.

[Hoosier]

As mentioned, Euro holds onto ridging over top just a bit more than GFS

[Michigander]

2 minutes ago, Buddy1987 said:

Man, I keep staring at that San Juan radar image loop and that eye is way too close for comfort, along with its trajectory if I am living in San Juan right now. It just refuses to want to move more north and west than progged, imo anyway.

Agreed. Maybe not the eye itself, but the eye wall looks like it could hit the northern fringe of the city.

[jbenedet]

St thomas got the southern half of the eye wall, and didn't get a respite from the eye.

[jojo762]

11am OFCL looks pretty much perfect for now. 

[friedmators]

That poleward turn is serious. 90 degrees basically in a short period of time.  If the turn is not as pronounced or happens a touch later, Western Florida could easily take a major hit.  I was hoping to give my friend in Fort Meyers some relief after this Euro run but i don't think I can.

[eyewall]

1 minute ago, jbenedet said:

St thomas got the southern half of the eye wall, and didn't get a respite from the eye.

Yeah that is true. I wonder how the winds compare in the southern eyewall to the northern side right now.

[NJwx85]

Just now, eyewall said:

Yeah that is true. I wonder how the winds compare in the southern eyewall to the northern side right now.

Fairly certain earlier reports had cat 5 winds in all four quadrants. 

[jojo762]

11am OFCL looks pretty much perfect for now. 

[friedmators]

Looks like recon turned around in the eye ha