ATL: IRMA - Models

[chris_fit]

18Z HWRF Running - Lets see if it trends back towards the 18Z GFS

[Kingslayer1254]

Looking at Satellite there is definitely an increased Northerly component to Irma's motion. The eye is passing well north of Puerto Rico. Perhaps this is why GFS was slightly east on this run.

I too noticed a hair of uptick on the direction while passing over PR. Hope that continues and then the turn...

[Steve]

Brutal hit for the GA and SC Coasts at +/-900mb. That's Cat 5 all the way. I don't buy it, but what I do get from the 18z GFS is even a smaller window of opportunity for personal action. It really looks like about 70 hours in S FL which would be midday Saturday. Y'all be sure to get done what you need to do and check on the elderly for their needs. Pets matter too, so please consider thier needs and their instinctive heightened sensitivity to the pressure falls. I had a good long model post going on my other phone before it died. I was thinking the GFS moving a little farther north would hook late, intensify in the straits and come up. That's not what happened. I think it's slightly too far to the east. Time to check everything else and get a nap in.

[TheStormExpert]

I'd ignore the GFS. It consistently keeps having to correct its north bias. Unless the vast majority of the models shift east I wouldn't buy into it for now.

[brghteys1216]

Don't forget the east bias with Matthew at 5 days out. UK Met was creepily accurate.

[Ken711]

Here’s the thing with Irma. Where that north turn happens will be critical, and despite how good the Euro and other models may be, they don’t have the accuracy at this range to nail down something that 20-40 miles is the difference between landfall or the east coast of Florida. Either way, it looks like Miami and surrounding areas will see winds gusting well over 100mph and I hope people take it seriously. We probably won’t know about the north turn until it actually happens...

For someone like me with no meteorological knowledge, what is the feature that makes the models so confident a turn will occur within that area? Thanks

Part of an upper-level trough currently centered near Minnesota.

Is there any chance this misses in timing or have they been constantly taking weather measurements?

[Bocadude85]

I'd ignore the GFS. It consistently keeps having to correct its north bias. Unless the vast majority of the models shift east I wouldn't buy into it for now.

The models will fluctuate 20-30 miles one way or another each run I would imagine..overall not much of a change with the 18z GFS. If you correct for its right bias then you would have a Florida landfall most likely.

[Hybridstorm_November2001]

Keep in mind everyone the Euro has under performed when it comes to Iram's depth/pressure. This is important as a deeper system will be more vertically developed and as such steered by higher level features, which can make a major difference track wise. I'm not saying the GFS will be right, only that is something to keep in mind.

[Steve]

I might have missed a page but JMA which has been a bit of a western outlier now just comes up the whole state of FL instead of getting to the eastern Gulf. It brings the Canadian high farther south, and it's already farther west than most models which forces the final left hook over to Arkansas instead of north or northeast of their like most of the other models have shown once inland.

[Cflstorm]

What time does the UKMET run and how often does it run? Where is the best place to find past runs?

[wxmann_91]

Keep in mind everyone the Euro has under performed when it comes to Iram's depth/pressure. This is important as a deeper system will be more vertically developed and as such steered by higher level features, which can make a major difference track wise. I'm not saying the GFS will be right, only that is something to keep in mind.

Given that the Euro has been the best performing track model with Irma by a long shot, I'm not sure how important that is.

[Hybridstorm_November2001]

Keep in mind everyone the Euro has under performed when it comes to Iram's depth/pressure. This is important as a deeper system will be more vertically developed and as such steered by higher level features, which can make a major difference track wise. I'm not saying the GFS will be right, only that is something to keep in mind.

Given that the Euro has been the best performing track model with Irma by a long shot, I'm not sure how important that is.

It could become very important soon, once the trough comes into play this weekend. We'll soon see.

[xironman]

Brutal hit for the GA and SC Coasts at +/-900mb. That's Cat 5 all the way. I don't buy it, but what I do get from the 18z GFS is even a smaller window of opportunity for personal action. It really looks like about 70 hours which would be midday Saturday. Y'all be sure to get done what you need to do and check on the elderly for their needs. Pets matter too, so please consider thier needs and their instinctive heightened sensitivity to the pressure falls. I had a good long model post going on my other phone before it died. I was thinking the GFS moving a little farther north would hook late, intensify in the straits and come up. That's not what happened. I think it's slightly too far to the east. Time to check everything else and get a nap in.

Why not, the tropical heat potential is there all the way, are you thinking the expected shear will degrade it?

[Hurricane Andrew]

HMON is slightly N...

[rockyman]

1 week ago, the 12z Euro had a major hurricane near the northern coast of Puerto Rico, moving toward south Florida.

1 week ago, the 18z GFS had a major hurricane several hundred miles NE of Puerto Rico, moving toward Bermuda.

[birddogsc]

That's the 4th consecutive model run with a landfall in SC. Hopefully they are paying attention to this.

I can tell you that the state is really paying attention to the model runs and has already activated several planning cells with more coming online tomorrow.

The thing about all these runs are that they are ending up in a fairly narrow band from about Savannah to below Charleston.

[Hybridstorm_November2001]

Everyone while model watching is interesting at times when in doubt always defer to the NHC track. Their track is typically more accurate than any one model. This is my Hurricane Rule of Thumb No. 1

[bamajammer4eva]

What's with the more NW movement after landfall? I noticed many Euro ensembles had the same thing. Is there any chance of that happening further south and going inland somewhere along the FL cost?

[Steve]

No (response to xironman). I think land interaction on Florida will degrade it. However, Bahamas to NC in the SW Atlantic has been a hot spot for several years in a row as I'm sure it often is in the warm AMO periods. I could see it intensifying and hitting as a 3 or 4 but 900mb in that GFS run assumes it stays over the water. I'd buy 930ish which is devastating enough for sure. NAVGEM is initialized, CMC should be rolling shortly and HWRF looks like it is going to do a number on at least the southern Bahamas which many of us were outlining mid last week as the #1 concern. Looks really bad so far on the HWRF run, like a freight train coming.

[MatthewsRevenge]

I can definitely see some weakening of Irma when it gets to around Florida. Can't see it retaining their strength by the time it reaches SC.