ATL: IAN - Models

[Fancy1001]

This is an emergency manager's worst nightmare that may be unfolding.

You mean A major hurricane heading near or in to the Tampa area with only about three days to prepare and evacuate.

[Fancy1001]

I don’t want to speak too soon, but it seems the HWRF has shifted northeast so far.

[Keldeo1997]

This is an emergency manager's worst nightmare that may be unfolding.

You mean A major hurricane heading near or in to the Tampa area with only about three days to prepare and evacuate.

I think what he means is that a few miles can be the difference between a little rain and wind or 130mph+ winds and 10+ feet of water rushing in. The Models are making it very hard for them.

[Fancy1001]

This is an emergency manager's worst nightmare that may be unfolding.

You mean A major hurricane heading near or in to the Tampa area with only about three days to prepare and evacuate.

I think what he means is that a few miles can be the difference between a little rain and wind or 130mph+ winds and 10+ feet of water rushing in. The Models are making it very hard for them.

Good point.

[Craters]

0z UK shifts east, and the GFS is back to its western Panhandle vacation… good to see our consensus is still clear as mud. I must admit I’m a little surprised… at this point we’re (likely) in the 72-96hr range until landfall and we’re still seeing some awfully large discrepancies between model runs. I feel this is the largest spread for this timeframe that we’ve seen in a long while, but perhaps it’s just selective memory. Least to say, I do not envy the position the NHC forecasters are being put into with Ian…

Last time I can remember something like this was with Laura in 2020. Most other models were showing a SW LA landfall but the Euro wouldn't budge on its Galveston landfall.

Yeah, the euro was an unmitigated mess for Laura, I remember it was still insistent on that Texas solution within 48 hours before finally caving. I’m starting to get the sense that the GFS might be dying on a similar hill with this insistence on a NW track, but who knows at this point. We’ll see how these runs have aged at the end of the week.

The thing, though, BeefStew, as I'm SURE you're very aware, is that the angle Laura had to the coast was very oblique,* similar to that of Ian, now, relative to the Florida peninsula. Just a small deviation at that kind of angle makes all the difference in the world. Ultimately, how far off was the Euro, ultimately? Two or three degrees? In most cases of Real Life®, such a tiny "error" means next to nothing. When it comes to things with these kinds of consequences, though, even being off by just a degree of angle could be catastrophic. The folks making decisions given conditions like these don't get paid enough, as far as I'm concerned.

The good thing about the Euro's bias, though, was that it was very consistent for the 2020 season, so decision makers could take that into account with some confidence. Here's a good article on that, if you get the time to read it: https://arstechnica.com/science/2020/09 ... vacuation/.

* I remember that whole thing very clearly. I live just south of Houston, and I was watching it -- with Storm2K front and center -- from a hotel in Austin.

[AtlanticWind]

HAFS has this just off SW Fla coast, I know this is still in experimental stage but
I think this is supposed to be a improvement on HWRF/HMON models.

[hiflyer]

NOAA49 up from Lakland AFB . The GIV for high altitude.

[Fancy1001]

The euro has finally started

[skyline385]

HAFS has this just off SW Fla coast, I know this is still in experimental stage but
I think this is supposed to be a improvement on HWRF/HMON models.

Its still experimental and in development, it will be an upgrade to the HWRF when finished. Right now, HAFS gives off weird solutions especially medium range so not meant to be taken seriously. Here's the verification for HAFS-A for Fiona, you can see some of the odd solutions it came out with.

[LarryWx]

0Z Euro 24 very slightly north of 18Z 30

[CrazyC83]

This is an emergency manager's worst nightmare that may be unfolding.

You mean A major hurricane heading near or in to the Tampa area with only about three days to prepare and evacuate.

I think what he means is that a few miles can be the difference between a little rain and wind or 130mph+ winds and 10+ feet of water rushing in. The Models are making it very hard for them.

That is indeed what I meant.

[LarryWx]

0Z Euro 48 slightly NE of 18Z 54

[Ed_2001]

At 72 definitely further east than 18z, very close to Pinellas county and likely landfall there based upon generally NNE direction from hour 48

Edit: by hour 96 it’s hugging the shore going very slowly northward, which is actually really similar to 18z

[CrazyC83]

Someone needs to cave for the 12Z runs. Otherwise, a Hurricane Watch will have to go out based on an uncertain forecast, and that can be so challenging to communicate.

[Fancy1001]

I think the euro model is actually worse than a direct landfall, because it stays just Outside of Tampa Bay for almost 24 hours continuously funneling water into the bay.

[Stormgodess]

Question: With a strong storm, that weakens.. let's say Ian gets to Cat 4 but weakens to Cat 2 before landfall. What about storm surge? Does the surge drop along with the weakening storm, or can it still hold on to pushing higher waters it gathered when much stronger?

Does that question make sense?

[Teban54]

Worth noting the GFS is the only model showing a complete stall at about 28N.

Ironically, 0z Euro shows a complete stall too. The million dollar question is how far away from the coast it happens.

This is giving me Dorian vibes...

[cheezyWXguy]

Question: With a strong storm, that weakens.. let's say Ian gets to Cat 4 but weakens to Cat 2 before landfall. What about storm surge? Does the surge drop along with the weakening storm, or can it still hold on to pushing higher waters it gathered when much stronger?

Does that question make sense?

Yeah it makes sense. And no, last minute weakening wouldn’t do hardly anything to reduce surge potential. It’ll have more to do with its size and strength over the day or so prior to landfall

[NDG]

0z Euro


0z UKMET

[Stormgodess]

Question: With a strong storm, that weakens.. let's say Ian gets to Cat 4 but weakens to Cat 2 before landfall. What about storm surge? Does the surge drop along with the weakening storm, or can it still hold on to pushing higher waters it gathered when much stronger?

Does that question make sense?

Yeah it makes sense. And no, last minute weakening wouldn’t do hardly anything to reduce surge potential. It’ll have more to do with its size and strength over the day or so prior to landfall

That is a massive area for surge, almost the entire gulf coast side of Florida. How do rescue groups even begin to decide areas to stage for this?