ATL: MILTON - Models

[jlauderdal]

[url]https://i.postimg.cc/TPSSqV5p/IMG-0520.jpg [/url]

12z HWRF shifted S from 06z… Wow directly into TB…

I realize it's unlikely to come to pass, but between the location and strength, that truly would be a doomsday scenario.

There is no doubt tb is in the bullseye, I dont see much wiggle room either north or south, north is worse in terms of surge. This looks very different than Helene in terms of people affected by a big surge.

[Jr0d]

Strongest run of ensembles of Euro yet.

https://i.imgur.com/6ZhD4nN.jpeg

I know we've talked about the stronger modeled storms are further north and weaker south, but it also looks like speed of the system (per the Euro ensembles) will play a role in N vs. S. impacts. Faster looks north. Slower looks more south.

I also noticed the GFS and ICON show slightly south turn after it passed Florida, after a ENE to NE jog before hitting the peninsula.

As always the timing of these turn is critical, if they even happen.

Despite the tightly clustered guidance, I do think there might be some higher than expected errors as these strong east moving storms in the GoM are rare

[NDG]

Close up look at latest 18z early tropical models. Expect a shift north over and narrowing of the cone by the next NHC advisory.
My heart aches for Tampa Bay.

https://i.imgur.com/GrRXWe2.jpeg

The cone size is not affected by models if I’m not mistaken
It is based on average error

They take average error more into consideration once the models are in better agreement like they have become this afternoon, so I guarantee you the cone of uncertainty will be narrower than just 6 hours ago.

[toad strangler]

18z earlies, slight shift left (north), lot's of I-4 riders here.
https://i.imgur.com/BIJ92Sv.png

I'm beginning to wonder about the prospect for this continual northward shift to continue all the way to Cedar Key.

There is a ton of real estate ahead of Milton. I would be very surprised if there wasn’t a period of shifts to the south. Windshield wipers move both ways!

[gatorcane]

12Z NAVGEM is definitely stronger than previous recent runs. 850MB (not surface) chart below, it is modelling a storm that grows significantly in size through the forecast period:

[Blown Away]

Systems moving OTS on a sharp ENE track instead of the traditional NE just off the Atlantic Seaboard tend error to the east of the track early on… I could see that little hump in the models where Milton moves over FL flatten a bit… JMHO

[NDG]

Close up look at latest 18z early tropical models. Expect a shift north over and narrowing of the cone by the next NHC advisory.
My heart aches for Tampa Bay.

https://i.imgur.com/GrRXWe2.jpeg

The cone size is not affected by models if I’m not mistaken
It is based on average error

True story. The cone has nothing to do with the confidence in forecast. It’s made up with circles of average margin of error over periods of time.

At the 11 AM discussion they mentioned this: "Users
are reminded to not focus on the exact forecast track or timing at
the longer range as the average NHC 4-day track error is about 150
miles."

The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.

[Canelaw99]

For those that want to read up on how the cone is created. Information directly from the NHC: https://www.nhc.noaa.gov/aboutcone.shtml

[Spacecoast]

[quote="NDG"
The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.[/quote]

I believe they are referring to +/- 150 miles, or ~300 miles wide.

[toad strangler]

The cone size is not affected by models if I’m not mistaken
It is based on average error

True story. The cone has nothing to do with the confidence in forecast. It’s made up with circles of average margin of error over periods of time.

At the 11 AM discussion they mentioned this: "Users
are reminded to not focus on the exact forecast track or timing at
the longer range as the average NHC 4-day track error is about 150
miles."

The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.

OK, Well, that would go Against everything I’ve understood about the cone previously. I’ve been wrong before

[cheezyWXguy]

True story. The cone has nothing to do with the confidence in forecast. It’s made up with circles of average margin of error over periods of time.

At the 11 AM discussion they mentioned this: "Users
are reminded to not focus on the exact forecast track or timing at
the longer range as the average NHC 4-day track error is about 150
miles."

The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.

OK, Well, that would go Against everything I’ve understood about the cone previously. I’ve been wrong before

No you’re right. This has been hashed out a number of times before, it’s based on average historical track error, not uncertainty in the moment. Rough eyeballing the cone and measuring the edge points at day 4 using the distance feature on RadarScope, I get a rough estimate of about 330 miles. I don’t think the forecaster is being precise with the 150 mile estimate, as there’s not really a reason to be, so I think it checks out.

Edit: canelaw’s link above shows track error margin at day 4 is 151 nautical miles, or about 174 miles. So a 350 mile wide cone at day 4 is to be expected.

[NDG]

[quote="NDG"
The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.

I believe they are referring to +/- 150 miles, or ~300 miles wide.[/quote]

So yes, 100 miles less wide than the 11 AM cone at day 4.

[jlauderdal]

At the 11 AM discussion they mentioned this: "Users
are reminded to not focus on the exact forecast track or timing at
the longer range as the average NHC 4-day track error is about 150
miles."

The current Cone at day 4 is nearly 400 miles wide, that's way more than the average error.

OK, Well, that would go Against everything I’ve understood about the cone previously. I’ve been wrong before

No you’re right. This has been hashed out a number of times before, it’s based on average historical track error, not uncertainty in the moment. Rough eyeballing the cone and measuring the edge points at day 4 using the distance feature on RadarScope, I get a rough estimate of about 330 miles. I don’t think the forecaster is being precise with the 150 mile estimate, as there’s not really a reason to be, so I think it checks out.

Its all stats, there is no massaging it from the nhc unlike a development area. Incredible we are getting another big surge event in a similiar area. Hopefully we can find some shear.

[gatorcane]

Indeed looks like NHC going with a major hurricane and mentioned it may have to increase the intensity in future advisories.

[jasons2k]

All — this is the model thread. Save the discussions about the cone, the NHC, speculation about advisories, etc., for the discussion thread please. Thanks.

[Gums]

Salute!

Well, praying again so soon, but this one looks like a Sarasota, Ft Meyers, and south of Tampa Bay for a surge effect.

Lottsa people east of landfall predictions so much more human impact than Hell-leen. Here's hoping strength numbers are too high.

Gums sends...

[TampaWxLurker]

18z Icon coming in slower and a little further south so far through 84 hours.

[BobHarlem]

18z icon takes a bit longer for landfall near Venice/Sarasota, but track is nearly identical to 12z, 966mb in the frame prior to this one.

[NDG]

18z Icon coming in slower and a little further south so far through 84 hours.

ICON might have sniffed this out early but it has been very inconsistent from run to run on track and timing.

[TampaWxLurker]

Interesting thing with that ICON run. Has it slowing down just before landfall, not full onshore until very early Thursday, then taking an almost due East track and exiting near Ft. Pierce/Vero Beach.