beanskip

I've seen hurricane AFDs not written that ominously!

"Not great Bob."

Rare 70-knot lower level jet with sub 990-low and warm front pushing ashore.

Even shy of severe threat, looks like non-storm related straight line winds that could gust over 50 mph.

Storm warnings for 13-15 foot swells.

Basically, a rare, major event for western Florida, among other places. 

12z Euro trending a bit east. Enough to matter for Cape Cod.

Saw this in the TLH discussion a few moments ago:

Area Forecast Discussion
National Weather Service Tallahassee FL
1108 AM EDT Fri Sep 1 2023

...New UPDATE...

.UPDATE...
Issued at 1108 AM EDT Fri Sep 1 2023

Torrential rainfall rates with an extremely moist air mass are the
main concern today. Earlier this morning, the weatherstem at the
Ochlockonee Boat Ramp in Franklin County had an instantaneous
rainfall rate of nearly 6.5 in/hr. PW values are in the extremely
moist 2.2 to 2.4 inch range. We also have a backdoor front our
Florida counties that will serve as a focus for further
development today. Will be watching trends closely to see if a
Flood Watch will be needed.

Man this thing is really trying to take a right turn. Steinhatchee may still be in the game for an eye passage at this rate. 

Tallahassee could really be dodging a bullet. 

This 18z Euro track is meterological chicken if I've ever seen it -- I mean it basically trucks due north until the very last second, then it gets pulled NE, then it kind of turns back NNE. That's going to make for some tense radar-watching in the morning. 

Close to nowcasting, but still some value from 18z runs imo. Both of the HAFS are reflecting the failure of Idalia to get west of 85.0 and are now showing slightly more eastern solutions. Every inch, foot and mile matters for the angle of approach and the windfield for Wakulla's coast, Tallahassee and others. 

85 W Longitude a pretty good measuring point for track. If it never gets on the plus side of 85, that will be good news for TLH. If it sneak across -- even for a bit -- that won't bode well. 

Why is there not a plane in the storm right now, in advance of the crucial, day-before-landfall 5 p.m. advisory?

Why does NHC still have a track that doesn't/barely includes Tallahassee/St. George even as all three hurricane models and the GFS show landfall there?

I mean, I never thought I'd be Criticize the NHC Guy, but I really don't get it. 

4 minutes ago, CoastalWx said:

Looks like HAFS-A and HAFS-B have landfall in Apalachee Bay just near and SE of Newport FL.

And HMON right on top of their positions -- remarkable agreement. 

EDIT: And the HWRF also in virtually the exact same spot  -- slight timing differences, but tracks are the same. 

1 minute ago, Brian5671 said:

CMC is not a great model for tropical events

Yeah I know.

I guess my point is, when's the last time you can remember an NHC cone where at 30 hours the CMC is 100 miles outside the cone and the GFS is outside it or just straddling its edge?

Gracious -- the CMC goes way west -- all the way to Apalachicola and then WEST of Tallahassee - I mean if this verified it would be pretty ugly for the NHC as this is WELL outside of the cone from their 11 a.m. advisory. 

3 minutes ago, 40/70 Benchmark said:

I made one post...and then one more because someone asked.

 

Yeah we don't want any amateur forecasts -- if that happens it might turn into a weather message board or something ... 

https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/093743.shtml?cone#contents

I'm rather flabbergasted by this map.

The cone doesn't even include St. George Island?

And barely touches TLH?

Wow. 

6z Euro moves just enough west to be a killer for Apalachee Bay. Looks like a hit around the Jefferson/Taylor line based on Tidbits maps, but if someone has  more detail, that would be appreciated.

This also is close enough to Tallahassee that hurricane force winds will surely impact the capital city -- you can't even believe how many trees will come down. 

6 minutes ago, SnowBeau said:

The 5AM NHC forecast didn’t have Idalia hitting 84.8W until 5PM, yet it’s already there at 8AM.  Just a wobble, or is that significant?

If you look at the track of the HAFS it actually has a bit of a bend in it -- starts at 84.7 then gets all the way out to 85.5 before turning back. Not saying that's right, but will be interesting to see if a westerly component materializes. 

It's pretty remarkable that the GFS and all 3 hurricane models show a direct hit on Wakulla and Leon counties -- in a little over 24 hours -- and both counties are only under a Tropical Storm Warning. I worry that an Apalachee Bay hit will catch many off guard. 

https://www.weather.gov/tae/

https://www.tallahassee.com/story/news/hurricane/2023/08/29/hurricane-idalia-updates-for-tallahassee-big-bend-models-track-florida/70705962007/

From the top of the TLH AFD:

National Weather Service Tallahassee FL
510 AM EDT Tue Aug 29 2023

...IDALIA EXPECTED TO SLAM THE FLORIDA BIG BEND AS A MAJOR HURRICANE
EARLY WEDNESDAY MORNING...
...New NEAR TERM, SHORT TERM, LONG TERM, AVIATION, MARINE, FIRE WEATHER, HYDROLOGY...

.NEAR TERM...
(Today)
Issued at 504 AM EDT Tue Aug 29 2023

You need to complete your preparations today if you live in the
Florida big bend. To put this system into the historical context,
there are NO major hurricanes in the historical dataset going back
to 1851 that have tracked into Apalachee Bay. None. Don`t mess
around with this. Follow the advice of your local emergency
management.

Coarse maps on Euro annoyingly hard to extrapolate when the 36-hour mark is the key window. 

WEST WEST WEST

0z GFS stays west with landfall near Alligator Point.

0z CMC makes huge jump west -- almost 100 miles -- and now is all the way over to St. Marks!

Is there some empirical data to support all of these anecdotes about past Gulf storms that ended up east of model projections? If that were a thing, wouldn't there be a study of it or something? 

Meanwhile the 0z NAM is all the way over to Apalachicola about 100 miles west of its 18z run.

Crappy model? Yes.

Umpteenth west trend today. Yes, too. 

4 minutes ago, dan11295 said:

In general there was an overall westward shift in the models at 18z. Obviously better for Tampa. As mentioned above, won't take much more of shift to be a major problem for Apalacheee Bay and Tallahassee. Even though TLH is inland, Idalia will be moving quick and that area hasn't seen the core of a strong hurricane in a very long time.

Yeah, Hermine was barely a Cat 1 and shut down Tallahassee for a week. Something like this would be beyond catastrophic given the pervasive tree canopy. 

8 minutes ago, beanskip said:

Uh oh -- pretty sizeable westward jog of the 18z Euro vs. the 12z run.

For Tallahassee/St. Marks/Apalachicola Bay, this is is a huge shift, more in line with the hurricane models and GFS. Another move or two like this and that area moves from the left to right side (or straight shot) of the storm. Night and day difference. The west trend has been clear all day -- I guess if it isn't going to hit Tampa Bay it must be fake news ... whatever.