ATL: IRMA - Models

[tolakram]

Hry guys the ridge is stronger and the trough is elongated and appears to cut off while another ridge is building behind it. It appears that this will cause Itma to stop and make sharp turn north some 50-200 miles off FL and send it up coast. Anybody else seeing this?

Not sure what you are asking. Right now the models are seeing this, the questions are when, where, and what direction it heads after turning.

[Vdogg]

Stronger and moving more westerly than expected. Possible shift again in the 00z run, most likely closer to Cuba. Even if this weakens over Cuba (or after brushing the coast) this would still be extremely powerful. Not yet taking the expected WNW turn to the next forecast point.

Well it was slightly North of the last forecast point and that Northwest turn isn't supposed to happen for another 20 hours. That said, I would think the faster it goes makes it more likely to be picked up by the trough.

[Vdogg]

Stronger and moving more westerly than expected. Possible shift again in the 00z run, most likely closer to Cuba. Even if this weakens over Cuba (or after brushing the coast) this would still be extremely powerful. Not yet taking the expected WNW turn to the next forecast point.

Is it odd of me to think that the turn won't happen as expected. I am watching models and this system seems to be trucking along straight west and it is happy doing so. However, I know these things have a mind of their own. Still way to early to tell.

I remember seeing this same discussion with Joaquin (or maybe it was Matthew). I remember it was just trucking along, and people thought there was no way it was going to make that turn. But then it stopped and stalled for a bit and made the turn on its exact forecast point. It's possible.

[ronjon]

Stronger and moving more westerly than expected. Possible shift again in the 00z run, most likely closer to Cuba. Even if this weakens over Cuba (or after brushing the coast) this would still be extremely powerful. Not yet taking the expected WNW turn to the next forecast point.

Well it was slightly North of the last forecast point and that Northwest turn isn't supposed to happen for another 20 hours. That said, I would think the faster it goes makes it more likely to be picked up by the trough.

Actually the trough is forecast to lift out by 72 hours - another shortwave is forecast to develop in the lower Miss valley in 5-6 days. It is this system that turns the storm north. If the storm is slightly faster, it may make it into the eastern GOM before that turn. Lots of variables in play 5-6 days out yet.

[txwatcher91]

The thing that needs to be watched is the energy diving from the Midwest. The reason the 06z GFS trended with a quicker turn and glancing blow on FL was because this energy was faster and stronger; thus breaking down the "thumb ridge" driving Irma WNW. If this does indeed occur, it will cause a quicker N turn and possibly spare Florida from a direct landfall. It's still too early to say for sure but the trends do need to be watched to see if 12z models continue to show this. This feature is only 84-108 hours out so it will start to be modeled better as it evolves.

[CrazyC83]

The thing that needs to be watched is the energy diving from the Midwest. The reason the 06z GFS trended with a quicker turn and glancing blow on FL was because this energy was faster and stronger; thus breaking down the "thumb ridge" driving Irma WNW. If this does indeed occur, it will cause a quicker N turn and possibly spare Florida from a direct landfall. It's still too early to say for sure but the trends do need to be watched to see if 12z models continue to show this. This feature is only 84-108 hours out so it will start to be modeled better as it evolves.

Even if Florida is spared, up the coast - and the Bahamas - would face a destructive hit though.

[txwatcher91]

The thing that needs to be watched is the energy diving from the Midwest. The reason the 06z GFS trended with a quicker turn and glancing blow on FL was because this energy was faster and stronger; thus breaking down the "thumb ridge" driving Irma WNW. If this does indeed occur, it will cause a quicker N turn and possibly spare Florida from a direct landfall. It's still too early to say for sure but the trends do need to be watched to see if 12z models continue to show this. This feature is only 84-108 hours out so it will start to be modeled better as it evolves.

Even if Florida is spared, up the coast - and the Bahamas - would face a destructive hit though.

Absolutely, it would change the impact zone from South FL landfall to scraping the coast or hitting SC/NC as a major hurricane. That's why this trend needs to be watched so closely because South Florida will likely be prepared, but if it pulls a Floyd scenario by just missing them and coming up the coast, SC/NC won't be as ready if they aren't closely watching this. Either way the Bahamas and Virgin Islands/PR look to get the worst of it in the short term.

[Vdogg]

Looks like the center of the eye just crossed 16.8 N. 8:00 am advisory had it at 16.7. Ever so slightly starting to gain latitude. Perhaps next advisory will have WNW, though if I'm being honest it's more like WWNW. It'll be interesting to see how 12z takes this into account.

[CrazyC83]

The thing that needs to be watched is the energy diving from the Midwest. The reason the 06z GFS trended with a quicker turn and glancing blow on FL was because this energy was faster and stronger; thus breaking down the "thumb ridge" driving Irma WNW. If this does indeed occur, it will cause a quicker N turn and possibly spare Florida from a direct landfall. It's still too early to say for sure but the trends do need to be watched to see if 12z models continue to show this. This feature is only 84-108 hours out so it will start to be modeled better as it evolves.

Even if Florida is spared, up the coast - and the Bahamas - would face a destructive hit though.

Absolutely, it would change the impact zone from South FL landfall to scraping the coast or hitting SC/NC as a major hurricane. That's why this trend needs to be watched so closely because South Florida will likely be prepared, but if it pulls a Floyd scenario by just missing them and coming up the coast, SC/NC won't be as ready if they aren't closely watching this. Either way the Bahamas and Virgin Islands/PR look to get the worst of it in the short term.

A category 3 impact for them would likely be as severe as a category 4 impact in south Florida. The trees farther north aren't as hardy to hurricane winds and building codes aren't as strong.

[BensonTCwatcher]

I don't think that we'll really know the US landfall solution until after Wed. Probably more like Thursday when the synoptic features are more in place. The break in the ridge and true timing of the trough are going to matter right when the angle of approach to the FL peninsula are most critical. We're getting down the most critical op runs and ensembles. UKMET is curious and I can't discount it given the history with this storm have to see if the EC ensembles shift.

[Blown Away]

12z Guidance... NHC S of most guidance, except for biggies Euro/Ukmet...

[SFLcane]

Official track should shift now tcvn has it turning NW sharply into Florida.

[wzrgirl1]

Changes in models is to be expected even up until landfall. The one thing we can ascertain is a very dangerous major hurricane will be in the Sfl area around Saturday evening and even though they may not get a direct hit (we still don't know) this will have as much impact minimally as Wilma according to Bryan Norcross.

[Bocadude85]

I don't think that we'll really know the US landfall solution until after Wed. Probably more like Thursday when the synoptic features are more in place. The break in the ridge and true timing of the trough are going to matter right when the angle of approach to the FL peninsula are most critical. We're getting down the most critical op runs and ensembles. UKMET is curious and I can't discount it given the history with this storm have to see if the EC ensembles shift.

If you compare last night's 0z run of the UKMET to yesterday's 12z run the UKMET actually shifted west..it has been slowly shifting west.

[gatorcane]

12Z guidance. Looks to have shifted back east:

[tolakram]

Models thread folks, and no model runs at the moment. I will be trimming posts back, don't take it personally. Please use the discussion thread if a post is not specifically model run related. Thanks.

[chris_fit]

Here is a quick run down of the latest available ENSEMBLE Runs @ 140 hours ...

06Z GEFS


00Z GEPS


00Z EPS

[CrazyC83]

12Z guidance. Looks to have shifted back east:

What is the CTCI? That seems like a huge outlier - is that a model or an extrapolation?

[gatorcane]

00Z UKMET is just east of Florida:

[ronjon]

What is the CTCI? That seems like a huge outlier - is that a model or an extrapolation?

CTCI Previous Experimental COAMPS-TC Forecast Interpolated Ahead 6 hr

Here's a nice summary of all models:

http://derecho.math.uwm.edu/models/models.html