ATL: IAN - Models

[Frank P]

My opinion models 5 days and out are just for general information and guidance. Once you get to days 4-5 then what the models produce become more relevant. Yeah the GFS has been all over the coast and the Euro has been mostly pointed at SW FL. But in the grand scheme of things it’s what have you done for me lately. Granted I have no idea where Ian will landfall, in the final analysis if it’s south of Tampa the give kudos to the Euro, but if it landfalls on the Panhandle then some credit should be given to the GFS. And if they split the difference then give both models credit, you certainly don’t want your model to be wrong 3 days out, that’s a given. My humble opinion.

[aspen]

Ian's UL environment becomes the most favorable later on Sunday through midday Monday on the HWRF, but it remains decent even through Tuesday night.



Afterwards, though, the UL pattern quickly becomes more hostile and should weaken Ian. Instead of UL flow expanding away from all quadrants of the storm, it gets directed into Ian from the W or SW.

[toad strangler]

I hear lots of talk about shear, but if this is a cat 3 or higher coming into the GOM, shear is not going to be much help. Look at Fiona which endured much higher shear than is forecast possibly for Ian almost throughout and maintained as a Cat 4. Strong storms create their own environment many times. Don't put much hope into shear causing much weakening if this is a strong cat 3 into the gulf.

Well I hear what you are saying but when you hear guys like Papin saying it you gotta listen right? It’s not hope. These guys are pros.

[cheezyWXguy]

Ian's UL environment becomes the most favorable later on Sunday through midday Monday on the HWRF, but it remains decent even through Tuesday night.
https://i.imgur.com/dgfM3o1.png
https://i.imgur.com/mjJGJPY.png

Afterwards, though, the UL pattern quickly becomes more hostile and should weaken Ian. Instead of UL flow expanding away from all quadrants of the storm, it gets directed into Ian from the W or SW.
https://i.imgur.com/wc4dIFX.png
https://i.imgur.com/VlT4QID.png

I’ve seen a few people mention Michael (not because of strength, but more because of setup), but I don’t remember much of the details as to why it was able to strengthen so much in the shear pattern it contended with. Is this a similar setup?

[Jelmergraaff]

ICON (12z) quite a shift to the north compared to the 00z-run, also later and a lot stronger.

[hohnywx]

 https://twitter.com/FloridaTropics1/status/1573693248656359424

[gatorcane]

ICON (12z) quite a shift to the north compared to the 00z-run, also later and a lot stronger.

Heading NE towards west coast of Florida and strong

[NDG]

12z ICON to the east and north of its previous 06z run, a little to the left of the NHC track.

[ConvergenceZone]

Regarding the intense shear in the gulf that people are talking about, yea, they were mentioning on the weather report this morning that due to dry air and very high amounts of shear that if we get lucky, we may only have a tropical storm to deal with in the Gulf of Mexico at time of landfall, but that the NHC is going to keep the strength as it is for now.............and residents should still prepare for a hurricane just in case. Also mentioning that a major hurricane is still very possible in the Carib,

[ScottNAtlanta]

I hear lots of talk about shear, but if this is a cat 3 or higher coming into the GOM, shear is not going to be much help. Look at Fiona which endured much higher shear than is forecast possibly for Ian almost throughout and maintained as a Cat 4. Strong storms create their own environment many times. Don't put much hope into shear causing much weakening if this is a strong cat 3 into the gulf.

Well I hear what you are saying but when you hear guys like Papin saying it you gotta listen right? It’s not hope. These guys are pros.

Even the pros will tell you that our forecasting ability of RI especially in this area of the Caribbean can be way under done. The pros at the NHC have also been saying that as well

[Jelmergraaff]

https://twitter.com/FloridaTropics1/status/1573693248656359424

Could eventually be positive if it takes (a lot) longer to reach the FL-coast, so that dry-air/shear may weaken it some. On the other hand, however, not passing over Cuba would mean an even stronger system entering the GOM.

[gatorcane]

Comparison of last two ICON runs. East shift:

[FLWeatherX]

Comparison of last two ICON runs. East shift:

https://i.postimg.cc/2j4jG2Mt/icon-mslp-pcpn-watl-fh114-trend.gif

https://twitter.com/wx_tiger/status/157 ... zhbPc98xZQ

Not sure but thinking East shifts might come back....

[gatorcane]

12Z GFS 6 hours:

[gatorcane]

GFS trend, slightly more SW:

[Abdullah]

12Z GFS is trending stronger and farther south than the 6Z GFS

At 48 hours - 979 millibars down to 970 millibars

[gatorcane]

GFS 48 hours and 9MB stronger than 06Z:

[gatorcane]

GFS trend slightly more SW:

[Jelmergraaff]

GFS (12z) will probably find the gap between the Yucatan and Cuba again. At +72h still 6 mb stronger than the 06z-run.

[cycloneye]

Goes thru Yucatán Channel.