ATL: IAN - Post-Tropical - Discussion

[wxman57]

Enjoyed my first day off since Sept. 11th yesterday. Still woke up at 3:30am but got to go back to sleep until 7am.

I have some thoughts on Ian. First of all, I don't think there is enough evidence to support an upgrade to Cat 5 prior to landfall in south Florida. If anything, Ian may have weakened a little prior to landfall. I don't think that Ian remained a hurricane while crossing Florida. You cannot differentiate between damage produced by wind gusts and by sustained wind (1-min average). I'm doubtful that Ian regained hurricane strength east of Florida. It was clearly undergoing an extratropical transition soon after emerging into the Atlantic. Lacking a core of convection, those FL winds are not a good indicator of true surface winds in such a storm, neither is coastal Doppler radar. I certainly believe Ian was ET prior to landfall in SC, likely with TS sustained winds with gusts 80-100 mph. Wind reports along the coast suggest it may have had 50-55 kt sustained winds with gusts 75-85 kts while offshore, weakening as it made landfall. I could find only one coastal station reporting sustained TS winds. That was Charleston with sustained wind in the 40s and gusts to 59 kts. I know there are other obs, but I don't think any supports hurricane intensity at landfall in SC. Finally, I think there's a 99.999999999% chance (possibly higher) that Ian will be retired.

Oh, and as for Ian's surge. I was monitoring the NHC peak surge maps and when I saw their map issued Tuesday afternoon, I was puzzled. Only 8-12ft into Ft. Myers? I was telling clients that 12ft might be okay for the beach area, but the surge could top 20ft up the Caloosahatchee river into downtown Ft. Myers. That map wasn't telling a good story. Surge height in bays and rivers is often twice that observed at the coast. In the graphics below, you can see NHC's peak surge map and a simple SLOSH plot showing possible surge into the bay. I think their inundation map looked good, showing many areas with water over 9 ft deep in Ft. Myers. We were telling clients in Tampa that they would not see a 4-6 ft surge. Maybe negative 4-6 ft with strong offshore winds.

http://wxman57.com/images/NHCSurgeTue.JPG
http://wxman57.com/images/SLOSHFMY.JPG

[Sanibel]

The saying "If it is coming right at you a week out you are probably safe" did not apply this time...

[SconnieCane]

Thanks Sconnie for the nod about the “Fists of God”.

It’s great to see them being discussed! They are the real power in a major hurricane.

Chuck

Aren’t those “fists of God” really just tornadoes (mesovorts) swirling around the eye wall - for us laypeople?

The Fists of God are almost horizontal as they drop from the sky. They don’t appear to have the rotation you see in tornadoes. They also don’t sound like a tornado. They sound like a fighter jet screeching by overhead before they drop down.

Chuck

They are a phenomenon

Chuck

So perhaps they are more like the microbursts you'd see in a land-based severe thunderstorm, but greatly amplified by being embedded within the ambient gradient winds of a major hurricane's eyewall?

[wxman57]

Went back to take a look at my first 7-day track for Ian. It was issued Wednesday morning, Sept. 21st, two days before the NHC issued their first track. By the time NHC started advisories, Friday, Sept. 23, our tracks were pretty close together. Ours go out 7 days because our clients have long lead times to prepare. Now, if only neither of us had shifted the track up to Tampa then back to Ft. Myers/Punta Gorda after that Friday's forecast. All in all, the forecasts for Ian were very good, but many of the public didn't get the message about the need to take this storm seriously. I can't believe that people actually stayed on Sanibel Island to ride it out. They really had no idea what was coming. Terrible loss of life. Barrier islands are never a good place to ride out any hurricane.

It's always difficult pinning down an exact landfall point when there is a narrow angle of approach at landfall. Just a slight heading change from western Cuba could make a difference between north of Tampa and Ft. Myers. I kept saying, storms encountering westerly shear in the Gulf always move faster than predicted and right of the forecast. GFS always tries to drive such a storm right into the shear. I'm not falling for that again.

http://wxman57.com/images/IanFirst.JPG

http://wxman57.com/images/IanFriday.JPG

http://wxman57.com/images/IanNHC.JPG

[THC_Scientist]

Wxman57 great analyst as always! You’re the best in this field, I always look forward to your outlooks during a storm. Keep saving lives.

[PandaCitrus]

Do we have some preliminary estimates of Ian's surge based on damage? Fort Myers Beach largely missed the eye and seemed to have onshore flow for hours and hours and hours which caused damage similar to Mexico Beach. Seems 15-18 feet seems a fair estimate.

Sanibel Island had less destruction, perhaps better building codes or slightly higher elevation on the island, so perhaps 12-15 foot surge on Sanibel. It does look like most gulf front condos had their first and second floors obliterated. This is one example from a condo on Sanibel, not sure if you can make an estimate from the video. Clearly, first 10 feet are gutted by surge and a lot of damage on that 2nd floor from water and wave action.

This is video from Sanibel Siesta on the Beach. 1246 Fulgur St, Sanibel

https://mobile.twitter.com/konradross/s ... m8mOErAAAA

Enjoyed my first day off since Sept. 11th yesterday. Still woke up at 3:30am but got to go back to sleep until 7am.

Oh, and as for Ian's surge. I was monitoring the NHC peak surge maps and when I saw their map issued Tuesday afternoon, I was puzzled. Only 8-12ft into Ft. Myers? I was telling clients that 12ft might be okay for the beach area, but the surge could top 20ft up the Caloosahatchee river into downtown Ft. Myers. That map wasn't telling a good story. Surge height in bays and rivers is often twice that observed at the coast. In the graphics below, you can see NHC's peak surge map and a simple SLOSH plot showing possible surge into the bay. I think their inundation map looked good, showing many areas with water over 9 ft deep in Ft. Myers. We were telling clients in Tampa that they would not see a 4-6 ft surge. Maybe negative 4-6 ft with strong offshore winds.

http://wxman57.com/images/NHCSurgeTue.JPG
http://wxman57.com/images/SLOSHFMY.JPG

http://wxman57.com/images/NHCSurgeTue.JPG

http://wxman57.com/images/SLOSHFMY.JPG

[blueskies]

Looking back to the 0Z 9/25 runs at where the models had FL landfalls:

0Z 9/25:
ICON Venice
CMC Cedar Key
GFS Destin
Euro Sarasota
UKMET Port Charlotte

12Z 9/25:
ICON Sarasota
CMC Apalachee Bay
GFS Apalachee Bay
Euro Tampa
UKMET Venice

0Z 9/26:
ICON Venice
CMC Apalachee Bay
GFS Apalachee Bay
Euro Cedar Key
UKMET Port Charlotte

12Z 9/26:
ICON Tampa
CMC Apalachicola
GFS Tampa
Euro Big Bend
UKMET Port Charlotte

0Z 9/27:
ICON Venice
CMC Big Bend
GFS Sarasota
Euro Venice
UKMET just N of Ft Myers

12Z 9/27:
ICON Port Charlotte
CMC Tampa
GFS just N of Port Charlotte
Euro Port Charlotte
UKMET 20 miles S of Ft. Myers

0Z 9/28:
ICON 15 miles S of Port Charlotte
CMC Venice
GFS Port Charlotte
Euro Port Charlotte
UKMET Port Charlotte

My grades on FL landfall only (i.e., excluding SC landfall) for 9/25-8 runs:

UKMET A-
ICON B
Euro C-
GFS D
CMC F

Thanks for this information Larry. I tried to create another version listing the landfall predictions from N to S.

0Z 9/25:

GFS Destin
CMG Cedar Key
Euro Sarasota
ICON Venice
UKMET Port Charlotte

12Z 9/25:

GFS Apalachee Bay
CMC Apalachee Bay
EURO Tampa
ICON Sarasota
UKMET Venice

0Z 9/26:

GFS Apalachee Bay
CMC Apalachee Bay
EURO Cedar Key
ICON Venice
UKMET Port Charlotte

12Z 9/26:

CMC Apalachicola
EURO Big Bend
GFS Tampa
ICON Tampa
UKMET Port Charlotte

0Z 9/27:

CMC Big Bend
GFS Sarasota
EURO Venice
ICON Venice
UKMET just N of Ft Meyers

12Z 9/27:

CMC Tampa
GFS just N of Port Charlotte
Euro Port Charlotte
ICON Port Charlotte
UKMET 20 miles S of Ft Meyers

0Z 9/28:

CMC Venice
GFS Port Charlotte
EURO Port Charlotte
UKMET Port Charlotte
ICON 15 miles S of Port Charlotte

[cheezyWXguy]

I have to say, the icon has really been impressing me lately. I haven’t looked up verification metrics, but I’ve been trying to keep tabs on its performance in storms I pay attention to since hurricane season 2020. It also performed well for the southern plains winter storms last year. The ukmet is the winner on landfall location for Ian specifically, but I remain hesitant to put confidence into it for future systems because of its lackluster track record. I agree with the B rating for the icon with Ian, but over the time I’ve been watching it, i would have to give it a B overall, compared to lower grade overall for the ukmet. The ukmet’s performance with Ian feels to me like taking an exam you only know half the answers to, filling in answer choice C for the rest, and somehow walking out with an A as your grade. Yeah I did well, but I would feel bad for anyone who tries to copy off me in the future.

Unless I find proof to the counter (I.e. selection bias in my “sample”), the icon has progressively moved up into my personal list of models to put some more weight on.

[Orlando]

Went back to take a look at my first 7-day track for Ian. It was issued Wednesday morning, Sept. 21st, two days before the NHC issued their first track. By the time NHC started advisories, Friday, Sept. 23, our tracks were pretty close together. Ours go out 7 days because our clients have long lead times to prepare. Now, if only neither of us had shifted the track up to Tampa then back to Ft. Myers/Punta Gorda after that Friday's forecast. All in all, the forecasts for Ian were very good, but many of the public didn't get the message about the need to take this storm seriously. I can't believe that people actually stayed on Sanibel Island to ride it out. They really had no idea what was coming. Terrible loss of life. Barrier islands are never a good place to ride out any hurricane.

It's always difficult pinning down an exact landfall point when there is a narrow angle of approach at landfall. Just a slight heading change from western Cuba could make a difference between north of Tampa and Ft. Myers. I kept saying, storms encountering westerly shear in the Gulf always move faster than predicted and right of the forecast. GFS always tries to drive such a storm right into the shear. I'm not falling for that again.

http://wxman57.com/images/IanFirst.JPG

http://wxman57.com/images/IanFriday.JPG

http://wxman57.com/images/IanNHC.JPG

http://wxman57.com/images/IanFirst.JPG

http://wxman57.com/images/IanFriday.JPG

http://wxman57.com/images/IanNHC.JPG

WOW! The NHC got it right on the first advisory. Why didn't SW FL evacuate knowing that a storm was coming?

[Michele B]

Thanks Sconnie for the nod about the “Fists of God”.

It’s great to see them being discussed! They are the real power in a major hurricane.

Chuck

Aren’t those “fists of God” really just tornadoes (mesovorts) swirling around the eye wall - for us laypeople?

The Fists of God are almost horizontal as they drop from the sky. They don’t appear to have the rotation you see in tornadoes. They also don’t sound like a tornado. They sound like a fighter jet screeching by overhead before they drop down.

Chuck

They are a phenomenon

Chuck

Huh. I guess I wouldn’t like to experience that!

[FLAloha]

Have lurked as a guest most times here as I have little meaningful academic weather expertise to share besides what I pick up here and elsewhere, but I’ve been lurking since before Charley, I was once posting as VeniceInlet, but lost that login. I checked in this time especially to extend my condolences to Sanibel, someone who has been here as long as I can remember. And also to those who have suffered loss from Ian’s storm surge. I consider myself blessedly lucky to only have fences and carport and trees down. They can easily be replaced. Hugs to all of you, Nancy

[CrazyC83]

Do we have some preliminary estimates of Ian's surge based on damage? Fort Myers Beach largely missed the eye and seemed to have onshore flow for hours and hours and hours which caused damage similar to Mexico Beach. Seems 15-18 feet seems a fair estimate.

Sanibel Island had less destruction, perhaps better building codes or slightly higher elevation on the island, so perhaps 12-15 foot surge on Sanibel. It does look like most gulf front condos had their first and second floors obliterated. This is one example from a condo on Sanibel, not sure if you can make an estimate from the video. Clearly, first 10 feet are gutted by surge and a lot of damage on that 2nd floor from water and wave action.

This is video from Sanibel Siesta on the Beach. 1246 Fulgur St, Sanibel

https://mobile.twitter.com/konradross/s ... m8mOErAAAA

Enjoyed my first day off since Sept. 11th yesterday. Still woke up at 3:30am but got to go back to sleep until 7am.

Oh, and as for Ian's surge. I was monitoring the NHC peak surge maps and when I saw their map issued Tuesday afternoon, I was puzzled. Only 8-12ft into Ft. Myers? I was telling clients that 12ft might be okay for the beach area, but the surge could top 20ft up the Caloosahatchee river into downtown Ft. Myers. That map wasn't telling a good story. Surge height in bays and rivers is often twice that observed at the coast. In the graphics below, you can see NHC's peak surge map and a simple SLOSH plot showing possible surge into the bay. I think their inundation map looked good, showing many areas with water over 9 ft deep in Ft. Myers. We were telling clients in Tampa that they would not see a 4-6 ft surge. Maybe negative 4-6 ft with strong offshore winds.

http://wxman57.com/images/NHCSurgeTue.JPG
http://wxman57.com/images/SLOSHFMY.JPG

http://wxman57.com/images/NHCSurgeTue.JPG

http://wxman57.com/images/SLOSHFMY.JPG

I know the WINK studios are at 5 feet above sea level (per Google Earth). It got up to the 2nd floor, so that would presumably be at least 15 feet along the riverfront. That's the best example I can think of now.

[jhpigott]

Death toll stands at 87 for now. UGH

https://www.nbcnews.com/news/us-news/bi ... -rcna50348

[Rail Dawg]

Thanks Sconnie for the nod about the “Fists of God”.

It’s great to see them being discussed! They are the real power in a major hurricane.

Chuck

Aren’t those “fists of God” really just tornadoes (mesovorts) swirling around the eye wall - for us laypeople?

The Fists of God are almost horizontal as they drop from the sky. They don’t appear to have the rotation you see in tornadoes. They also don’t sound like a tornado. They sound like a fighter jet screeching by overhead before they drop down.

Chuck

[Sanibel]

I went to the Town Counsel at the Crown Plaza and got the point in that the spoil islands were not a good idea...Their saving money by making spoil islands came at more expense than they were worth...A continuous raised, piered span would have survived intact and made getting back to the island much faster and less expensive...The Causeway failed where Earthen Abutment met concrete span...And the spoil islands returned to the sea...

[tropicwatch]

If the remnants of Ian enters the Atlantic and becomes a sub-tropical system. Will it still be named Ian?

[jconsor]

The remnants of Ian are becoming a hybrid low near the mid-Atlantic coast with a shallow warm core (mainly 850 mb and above). The interaction between this very slow-moving low and a strong high pressure system over E Canada and the NE US is creating a major, multi-tidal cycle coastal flooding event from northeast NC to southern NJ that will continue into Wed.

 https://twitter.com/yconsor/status/1576955776790249472




 https://twitter.com/yconsor/status/1576958021473013760




 https://twitter.com/yconsor/status/1576966624057647106

[Rail Dawg]

Aren’t those “fists of God” really just tornadoes (mesovorts) swirling around the eye wall - for us laypeople?

The Fists of God are almost horizontal as they drop from the sky. They don’t appear to have the rotation you see in tornadoes. They also don’t sound like a tornado. They sound like a fighter jet screeching by overhead before they drop down.

Chuck

[chris_fit]

Where did the Ian Models thread go?

[tolakram]

Where did the Ian Models thread go?

2022 archive

https://www.storm2k.org/phpbb2/viewforum.php?f=93