ATL: IRMA - Models

[otowntiger]

FWIW, something to note if this wasn't posted already.


 https://twitter.com/RyanMaue/status/903031486768717824

The majority of those send it out to sea, but of course some do bring it to the upper east coast, but the mean seems to keep it offshore.

[Exalt]

I would completely disregard this whack GFS run.. Sending the storm into a high? Peaking at 897 then only 12 hours later weakening to 933? And the wind forecasts don't correspond at all. I don't buy any of it. I do believe this could reach Cat 5, but to go from 5th strongest hurricane on record to a mid-high Cat 4 so quickly doesn't seem to foot the bill, unless something really goes wrong.

[AutoPenalti]

FWIW, something to note if this wasn't posted already.


 https://twitter.com/RyanMaue/status/903031486768717824

The majority of those send it out to sea, but of course some do bring it to the upper east coast, but the mean seems to keep it offshore.

That's half actually...

[KWT]

Big spread on the 12z ECM ensemble there. I'd say the mean looks a little further north than it was for the 00z run but plenty of runs are close enough to the east coast to require serious watching...

PS, here is the same runs out to 240hrs:



So most of the runs that hit the states are well past 240hrs still...

[ConvergenceZone]

I still think 10 to 15% chance of it not recurving is still reasonable based on location and strength and current models. Note that I said recurve, NOT Fish

[SouthDadeFish]

18Z HWRF forecasts RI over the next 24 hours and has shifted much farther SW from the 12Z run.

[RL3AO]

18Z HWRF forecasts RI over the next 24 hours and has shifted much farther SW from the 12Z run.

It handled Harvey very well. At least in the GOM.

[Ivanhater]

Of course this favors a recurve just based on climatology. What's unique about this one is quite a few operational and ensemble runs are showing a threat to the Southeast U.S....just last week as we were watching Harvey, models.had this turning well east of the Islands on the 10 day run. Those 10 day runs last week were off substantially

[KWT]

Just looking at the 18z GFS ensembles, 18z op is pretty much right on the mean.

Interestingly more than a few start to bend back westwards around 240hrs, especially a few of the early recurvers...

Some of the runs end up still heading WNW towards Florida, probably more spread than the 12z it seems.

Also many powerful majors in there as well this time, thats the biggest difference between the 12z suite.

[Hurricaneman]

I'm expecting the 0zGFS to show this farther west than the 18z

[SouthDadeFish]

For reference here is the 126-h 18Z HWRF forecast:

[1900hurricane]

I would completely disregard this whack GFS run.. Sending the storm into a high? Peaking at 897 then only 12 hours later weakening to 933? And the wind forecasts don't correspond at all. I don't buy any of it. I do believe this could reach Cat 5, but to go from 5th strongest hurricane on record to a mid-high Cat 4 so quickly doesn't seem to foot the bill, unless something really goes wrong.

The sudden drop of intensity is due to the model's resolution drop that occurs beyond tau 240.

[SFLcane]

Not probable but those are some 930mb's near Florida.

[KWT]

What really stands out from those GFS ensembles is alot of the eastern systems are the weaker storms that don't do much...the stronger storms are all further SW closer to the states. Given this one IS developing and strengthening, it does raise alarm bells to me.

[AxaltaRacing24]

FWIW: Strongest signal I have seen with the ensembles sending it farther west

[Dean4Storms]

You have to be careful with the recurve statistics with a storm this high in latitude as much of those statistics are including storms in latter half of Sept., Oct and into Nov. when the Jet is much more amplified as we head into Fall in the Northern Hemisphere. Early Sept. the Atlantic Ridge is much more robust climatology speaking and could keep Irma on a more westward trajectory unless as the GFS depicts that trough to its NW out east of the Islands creates enough backing off of the ridge to allow a more NW motion where it could get picked up by the CONUS trough out in the 240hr range. If the ECM is correct and you have less trough influence on the Ridge then a more westerly motion is very plausible and being further south in latitude misses a big enough turn to not miss the US mainland. Right now I would lean toward the ECM simply due to such a strong ridge depicted and has been for much the past month.

[AxaltaRacing24]

What really stands out from those GFS ensembles is alot of the eastern systems are the weaker storms that don't do much...the stronger storms are all further SW closer to the states. Given this one IS developing and strengthening, it does raise alarm bells to me.

Silly question, but how would one determine the strength of these ensembles?

[AutoPenalti]

The trend is definitely your friend here, in our case, our enemy.

I'm still leaning on a 45% recurve and 55% with landfall or close proximity from SE FL to the OBX.

[SFLcane]

What really stands out from those GFS ensembles is alot of the eastern systems are the weaker storms that don't do much...the stronger storms are all further SW closer to the states. Given this one IS developing and strengthening, it does raise alarm bells to me.

Silly question, but how would one determine the strength of these ensembles?

See my post above some really intense..

[NDG]

This would probably be record breaking low mid level heights across the SE US for early Sept if GFS was to be right.
The weird thing is that ensembles don't show the PNA to go so crazy positive and the NAO going negative.