ATL: IRMA - Models

[stormreader]

Not buying the brick wall turn

You don't have to buy it but nature often sells it. Matthew and Hermine last year both made abrupt turns. It's fairly common.

Downstream features that have not deveoped yet are terribly tricky to forecast. IF that low does not develop than no sharp north turn..

Well its true, that some of the ensemble don't have the radical north turn. They take the storm further west into the eastern Gulf of Mexico with a landfall in the big bend or even Appalachicola area.

[Aric Dunn]

models are still betting some sort of a low to develop over the MS valley... not buying into it yet..

I don't see it either ? There's really not much coming from the nw atm

It's subtle but it's there. Shortwave troughs going trough a longwave ridge get lost since the relative vorticity of the shortwave gets lost in the negative vorticity of the ridge.

About 132 hours.. same as yesterday with most of the models.. that is the culprit.. without that low forming no sharp north turn

https://www.tropicaltidbits.com/analysi ... 0&ypos=375

[Frank P]

No sharp NE turn this run. Trend is bad for the GOM

Disagree, this is not bad at all for the GOM ... this run doesn't even make the GOM... how can this be bad?

Well, I'm only referring to the extreme SE Gom, which with a shallower trough would allow entry there, before a move north along the Fl West Coast.

OK, I can buy that clarification and that certainly still is on the table... going to be a lot of model watching in the coming days.. I don't want anyone to get this, but no one more than me.. not going to build a third house..

[Michele B]

Trough looking about the same compared to the 06z run so far. Maybe will show a more northern turn before 80W.

We on the west coast of FL hope for that, sorry Miami, FLL WPB

[stormreader]

That's currently over NE/SD right?

Looks like that feature is currently off the Pacific coast. It moves north into British Colombia and then dives southeast behind the main trough. It's a subtle feature, so it's hard to track unless you know what you're looking for.

in 'looking at this clip, look at the high pressure retro grading significantly allowing Jose -to -be to go north out to sea could be enough to allow Irma to start turning north sooner- maybe?? Hopefully??

;My experience is that it usually works the other way around. Meaning future Jose, is completely blocked and never gets close to the East coast, but Irma well ahead, is forced further west than you would anticipate to get around the large ridge.

[otowntiger]

Paralleling the east coast and never making landfall in Florida is still very much in play.

Yep, I think a lot of widely diverse tracks are still in play.

[Blown Away]

Both the GFS/GEM don't allow Irma to recurve OTS after Florida, pushes her into the Carolinas and goes NW... Not hitting the CONUS looking less likely by the hour... Hope the trend continues north, the latest GFS was a bit better for the NE Caribbean, PR, Hispaniola, and Cuba... Bahamas, well nothing to say but prepare...

[floridasun78]

https://weather.us/model-charts/standard/broward/windspeed-barbs/20170910-2100z.html

https://weather.us/model-charts/standard/florida/windspeed-barbs/20170911-0000z.html

So the latest GFS would do this to SE FL.. it's pure model fantasy, but quite interesting to look at.

this what miami was lucky with Andrew because want into south dade

[MrJames]

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 04.09.2017

HURRICANE IRMA ANALYSED POSITION : 16.7N 52.7W

ATCF IDENTIFIER : AL112017

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 04.09.2017 0 16.7N 52.7W 965 69
0000UTC 05.09.2017 12 16.3N 54.8W 968 75
1200UTC 05.09.2017 24 16.2N 57.2W 963 80
0000UTC 06.09.2017 36 16.6N 59.3W 963 73
1200UTC 06.09.2017 48 17.3N 61.7W 961 78
0000UTC 07.09.2017 60 18.0N 64.3W 958 78
1200UTC 07.09.2017 72 18.6N 67.0W 949 90
0000UTC 08.09.2017 84 19.2N 69.4W 949 83
1200UTC 08.09.2017 96 19.5N 72.4W 979 62
0000UTC 09.09.2017 108 19.8N 74.5W 970 67
1200UTC 09.09.2017 120 20.5N 76.6W 964 60
0000UTC 10.09.2017 132 21.3N 78.1W 962 68
1200UTC 10.09.2017 144 22.6N 78.8W 945 83

Mapped it via Google. UKMet sticking with the shredder run.

[Steve]

HWRF is now running. at 39 hours it's NW of the 06Z position. I'm calling it:

06Z - 17.5N 60.3W @ 934mb
12Z - 17.8N 60.8W @ 930mb

https://www.tropicaltidbits.com/analysi ... 0412&fh=39

[pcolaman]

Looks like that feature is currently off the Pacific coast. It moves north into British Colombia and then dives southeast behind the main trough. It's a subtle feature, so it's hard to track unless you know what you're looking for.

in 'looking at this clip, look at the high pressure retro grading significantly allowing Jose -to -be to go north out to sea could be enough to allow Irma to start turning north sooner- maybe?? Hopefully??

;My experience is that it usually works the other way around. Meaning future Jose, is completely blocked and never gets close to the East coast, but Irma well ahead, is forced further west than you would anticipate to get around the large ridge.

And doesn't look like it gets as low as the trough passing atm

[Happy Pelican]

Paralleling the east coast and never making landfall in Florida is still very much in play.

My opinion, not a Professional, but that's what I keep feeling. Don't know why, but as Irma starts her turn north, I think the models are going to come East. That's not to say, East coast of Florida isn't going to see some damaging winds and flooding but fingers crossed they're spared the full brunt.

[Blown Away]

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 04.09.2017

HURRICANE IRMA ANALYSED POSITION : 16.7N 52.7W

ATCF IDENTIFIER : AL112017

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 04.09.2017 0 16.7N 52.7W 965 69
0000UTC 05.09.2017 12 16.3N 54.8W 968 75
1200UTC 05.09.2017 24 16.2N 57.2W 963 80
0000UTC 06.09.2017 36 16.6N 59.3W 963 73
1200UTC 06.09.2017 48 17.3N 61.7W 961 78
0000UTC 07.09.2017 60 18.0N 64.3W 958 78
1200UTC 07.09.2017 72 18.6N 67.0W 949 90
0000UTC 08.09.2017 84 19.2N 69.4W 949 83
1200UTC 08.09.2017 96 19.5N 72.4W 979 62
0000UTC 09.09.2017 108 19.8N 74.5W 970 67
1200UTC 09.09.2017 120 20.5N 76.6W 964 60
0000UTC 10.09.2017 132 21.3N 78.1W 962 68
1200UTC 10.09.2017 144 22.6N 78.8W 945 83

Mapped it via Google. UKMet sticking with the shredder run.

Seems Ukmet initializes .1 S and has Irma making down to 16.2 within 24 hours... Doesn't look that way as of now...

[otowntiger]

I think the pressures on the GFS, given all the land interaction, is way too low and unrealistic. Anybody agree??

[p1nheadlarry]

CMC landfall in S FL but shifts track east with a second hit in NC

So gfs and CMC move east to a Carolinas hit. Euro comes back from OTS to a Carolinas hit. Maybe, just maybe, we're dialing in on some sort of consensus. Ensembles should be interesting.

Isn't that, literally, the exact path of Donna?

Donna made landfall further south than the OBX, but it's close

[MississippiWx]

The biggest key won't be sampled by weather data until another day or two. The shortwave energy that dives south into the SE US comes from the upper low that is spinning off California. It goes due north over the top of the ridge and then dives south on the models. If this energy is not predicted correctly, it will have major implications on track. If it's stronger and faster than advertised, Irma might go east of Florida. If weaker or slower, then the opposite.

[Frank P]

No sharp NE turn this run. Trend is bad for the GOM

Disagree, this is not bad at all for the GOM ... this run doesn't even make the GOM... how can this be bad?

It's the trends. We've gone further west each run, and more ensemble members are making it into the north/east gulf since Friday.

I don't disagree at all, many models have trended west over the past 12 hours... all I'm saying is the latest GFS did not trend to the GOM.. yes, its just one model, but who's to say this is not the beginning of more models trending to the east.. I have no idea, but I'll take every model that trends more east and be quite thankful for them... so we just continue to model watch .. would love to see this afternoons EURO keep that trend east going too..

[stormreader]

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 04.09.2017

HURRICANE IRMA ANALYSED POSITION : 16.7N 52.7W

ATCF IDENTIFIER : AL112017

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 04.09.2017 0 16.7N 52.7W 965 69
0000UTC 05.09.2017 12 16.3N 54.8W 968 75
1200UTC 05.09.2017 24 16.2N 57.2W 963 80
0000UTC 06.09.2017 36 16.6N 59.3W 963 73
1200UTC 06.09.2017 48 17.3N 61.7W 961 78
0000UTC 07.09.2017 60 18.0N 64.3W 958 78
1200UTC 07.09.2017 72 18.6N 67.0W 949 90
0000UTC 08.09.2017 84 19.2N 69.4W 949 83
1200UTC 08.09.2017 96 19.5N 72.4W 979 62
0000UTC 09.09.2017 108 19.8N 74.5W 970 67
1200UTC 09.09.2017 120 20.5N 76.6W 964 60
0000UTC 10.09.2017 132 21.3N 78.1W 962 68
1200UTC 10.09.2017 144 22.6N 78.8W 945 83

Mapped it via Google. UKMet sticking with the shredder run.

And then you see the UKMET images implying the sharp turn north late in the forecast run. GFS leveled out that south dip over Cuba. Will see what Euro does. But leveling out that south dip, I think, implies somewhat further west--so direct hit on S Fl. or even a tad further west than expected into extreme E GOM.

[Michele B]

CMC landfall in S FL but shifts track east with a second hit in NC

In other words, a reincarnation almost perfectly of Donna.

What I always liked about the Donna analog was the fact that it formed at almost the exact same date (Aug 29) in the Cabo Verde Islands area. Donna did not intensify quite as quickly as Irma, but still was a major hurricane well out to sea. Donna peaked at Cat 4 before entering the Keys and turning up into Fl and then paralleling the East seaboard. The similarities are obviously there.

Not sure about the stats on Donna while out in the Eastern Atlanta We didn't have the technology or instruments To track them like we do today

[Steve]

HWRF still NW of 06Z

06Z - 17.85N 61.1W (930mb)
12Z - 18.15N 61.6W (925mb)


Aside to Rock:

Run the 06Z IR4 simulated off HWRF-P as it finally finished. Dynomat in the house.
https://www.tropicaltidbits.com/analysi ... 0&ypos=600