ATL: HARVEY - Models

[South Texas Storms]

Gfs is so bad it's pathetic

GFS has been a major joke this year but you got to remember it's a forecast model and it wasn't only designed to track tropical systems it was designed to predict the environment in the air overall

It's a global weather model in 2017. Consistently failing with TC genesis drastically affects its ability to forecast the upper air patterns globally at days 5 to 10.

Yep, it's been bad everywhere since the "upgrade". It looks like the NHC's fears were correct (they strongly opposed this "upgrade").

Canadian is very close to (if not already) being a better model than the GFS in my opinion.

[RL3AO]

Some of the Euro ensembles do track this over Haiti, but there is a very strong signal with ~40% of the ensembles having a major hurricane in NW Caribbean.

 https://twitter.com/RyanMaue/status/897088691201609728

[gatorcane]

The GFS and CMC look to have a PV streamer that dips down from the Central Atlantic around days 4 and 5 which induces a lot of shear over this invest as it heads WNW just NE of the Lesser Antilles. But if this invest manages to get north of the islands looking at the GFS and CMC upper environment, conditions look favorable for reintensification. The ECMWF may keep this just south enough to avoid the shear from that streamer. For now the ECMWF is through the Caribbean/islands but that could change in subsequent runs.

GFS Shear map at 102 hours showing the PV streamer with invest just east of NE Lesser Antilles

[RL3AO]

The GFS and CMC look to have a PV streamer that dips down from the Central Atlantic around days 4 and 5 which induces a lot of shear over this invest as it heads WNW just NE of the Lesser Antilles.

I'm growing more and more skeptical of this missing islands and not being a Caribbean system. This is going to be a disorganized system for at least three more days. It should move pretty much due west during that time. When you consider the models favor the western part of the system to develop now as well, that makes a Caribbean system even more likely than it appeared yesterday.

[KWT]

ECM solution looking decent to me IMO, the GFS is very much all over the place at the moment with regards to whether or not this even forms in the first place.

Of course the Islands may help to keep this one in check but its very possible if it avoids the shear in the Atlantic it will already be a hurricane by the time it gets to the islands. Models suggests there shouldn't be an exit path for this one, its going to get into at least the Caribbean area, its just whether its over/south or just to the north of the islands

[gatorcane]

12Z models (note many are not on this chart):

[Emmett_Brown]

Question about global model initialization; now that the Best Track position of 91L has been moved 10 deg to the west, will this new position be used for initialization of the models, and if so, when is the next run that would have the new position?

[RL3AO]

Question about model initialization; now that the Best Track position of 91L has been moved 10 deg to the west, will this new position be used for initialization of the models, and if so, when is the next run that would have the new position?

The statistical models (like most of the ones in the spaghetti plots above) will account for it at the 12z run. The dynamical models like the GFS, Euro, UKMET, etc couldn't care less what the NHC labels as the center of the invest. They're gonna analyze the atmosphere and solve the equations.

[emeraldislenc]

Thanks for all the information y'all do a great job explaining!

[Steve]

Gotta say I'm not thrilled with the European this morning. I don't think any Gulf of Mexican or resident of South Florida or the Keys wants the trend to maintain. Yesterday's 12z run ended with a strong system just south of Florida. Now it's showing a hurricane just north of the NE side of the Yucatan Peninsula. There's no way out for that but through land. Usually 10 days out you can just say screw it. But whenever the European is on board, it's worth at least a pause.

[KWT]

Whilst that is a very small sample set gatorcane, its very noticeable that the models that do something with the western 91L takes it all the way west, whilst those that tune into the CV end of it, recurve it.

Seems to me that given the relocation today, the western models will be right and therefore this will keep further south.

[JPmia]

This is the first season I can recall where I am having much less faith in what the models are telling us. And then to learn above that the NHC was not supportive of the GFS upgrade makes it even more concerning. I feel we have even less confidence about the future of 91L than normal.

[wxman57]

Question about global model initialization; now that the Best Track position of 91L has been moved 10 deg to the west, will this new position be used for initialization of the models, and if so, when is the next run that would have the new position?

The system that the models are developing is in the vicinity of 13N/35W, not way back at 25W. Rotation is easy to see on the visible loop. Here's a screenshot. The red crosshairs is where I see the center.

[tolakram]

Hi all,

keep in mind these model threads do not work like other Storm2K threads, off topic posts will be deleted without warning. We are trying to keep model threads focused on model runs and the valuable conversation that can happen discussing those runs. I fully realize some off topic posts are harmless so I hope all of you understand when a post that does not contribute to this thread is removed.

Thanks for your cooperation.

[gatorcane]

00Z NASA model has the 850mb vort near NE tip of Dominican Republic in a week:

[KWT]

Yeah its pretty clear where it is located Wxman57, as said in the other thread, its kinda got a classic pre-formation look to it.

Models do seem to be shot for some reason this year, more so than normal. Wonder what the 12z suite shows...

[AubreyStorm]

Hi to ALL!

This is true?
06z GFS and 06z Canadian do not develop #91L

[gatorcane]

12Z GFS out through 30 hours so far appears to be favoring eastern vort.

[WeatherEmperor]

Through 54hrs appears totally lost




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[Alyono]

GFS forming eastern system