ATL: IRMA - Models

[ronjon]

Trof lifting out on GFS already by 72 hrs.

[SouthFLTropics]

Even though it's a little further North I don't think it is going to make a difference in the long run. Look at the bridge of high pressure building above it as the trough lifts out.

[AxaltaRacing24]

[Steve]

Looked like it was maybe riding/hooking just north of the islands as the track smooths a little more WNW again and runs the north side of Hispaniola through 66 and aiming right at the southern Bahamas. But will it pull north, south or go through them?!

remember there is a lot of new data .. so some changes are likely..

There’s no need to discount it. The trend started at 12z with further north adjustments and 18z is continuing that trend. This is very significant especially with upper air data assimilated in.

I don't think he was discounting it - just cautioning that there would likely be some changes. And then the Gulfstream IV data gets in the 00z suite, so we'll know even more then.

[Kingarabian]

18z GFS:

[Big Easy Breeze]

It's time for the NAMs to be useful on the continent. Ignore the west bend of Irma at the end of the run but focus on the upper pattern.

250mb wind streamlines:
https://www.tropicaltidbits.com/analysi ... s=0&ypos=0

500mb Height Anomalies
https://www.tropicaltidbits.com/analysi ... 0&ypos=400

z500mb Vort & Wind
https://www.tropicaltidbits.com/analysi ... 0&ypos=300

MSLP over 500mb
https://www.tropicaltidbits.com/analysi ... 0&ypos=300

Moral of the NAM is that the trough that moves out in 3.5 days does not pull up Irma.

So does that mean it goes into the gulf?

I don't think so unless it gets in the extreme SE Gulf around the Keys and comes up on FL. I think what Aric alluded to was a potential suspect cutoff down in the lower MS Valley. But the way the winds are at 200 and 250, I don't really think Irma could get very far in the Gulf unless it was really far south or if it pinched off that edge near the keys if the JMA/NAVGEM/CMC are right with the little hook up and in.

Less we forget Katrina? Also, as we all know with a deepening Hurricane, it will have an influence on the high pressure over its top.

Looking at the official NHC track, the track has Irma tracking closely along the northern coast of Cuba through day 5 from today. Beyond that it is a HUGE guess.

Bottom line; after 5 days, no one is off the hook.

[Frank P]

the poor Bahamas just can catch a break...

[stormreader]

Trof lifting out on GFS already by 72 hrs.

I know. Its early Sept. It was deep, but very short-lived. High pressure build in behind it???? Quite a bit farther west than anticipated???? Talking about runs during the next day or two.

[SouthFLTropics]

If anything this is going to be worse for Florida as it is going to have less interaction with land than it would have previously had.

[Aric Dunn]

bends back west through 90 hours..

[Kingarabian]

18zz GFS steering trend:

[Frank P]

Trof lifting out on GFS already by 72 hrs.

I know. Its early Sept. It was deep, but very short-lived. High pressure build in behind it???? Quite a bit farther west than anticipated???? Talking about runs during the next day or two.

All eyes on the two ridges..

[xironman]

That's a monster trough, DC is going to have temps 20 degrees below normal on Wednesday.

That has the new balloon data from the Midwest as well?

From as far as I know not yet

[AxaltaRacing24]

A bit faster but same area

[crimi481]

So if that trough pulls out - as mentioned here - what stops Irma from going west into Gulf? (via the Keys)

[Alyono]

run may be far worse for Florida. It is farther north which means no Cuban interference

[Kingarabian]

GFS trend from the past 4 runs:

[Steve]

Out to 96 Hours running across the central Bahamas and just north of Eastern Cuba. Like the HWRF and HMON it's booking it WNW. It will likely hook up at some point. This is valid through Friday at 1:00pm. Maybe 200 miles separate SF and Irma!
https://www.tropicaltidbits.com/analysi ... 0418&fh=90

[Big Easy Breeze]

Trof lifting out on GFS already by 72 hrs.

I know. Its early Sept. It was deep, but very short-lived. High pressure build in behind it???? Quite a bit farther west than anticipated???? Talking about runs during the next day or two.

Like I said and what I have been telling the family. Beyond the OFFICIAL 5 day forecast period of the NHC, everything is on the table. But truthfully, beyond 3 days, there is large room for error. But the NHC has been on their game A LOT. Give them props.

[stormreader]

18z GFS:

Say again what I said on last model runs. A track that dips less down toward Cuba, keeping storm well off Cuba coast, could be a harbinger of a farther west movement. Could mean the high is centering itself less down right on top of the storm there, but extending out farther west.