ATL: DORIAN - Post-Tropical - Discussion

[SconnieCane]

Unreal. They got completely destroyed.

https://www.facebook.com/wxchasing/vide ... 142664492/

As expected, the damage in non-surge inundated areas is Michael-like or slightly worse; with some houses split open and the wood splinters that once comprised their walls strewn across the landscape reminiscent of violent tornado aftermath, and others with only a small portion of the roof missing. The difference likely comes down to construction quality and whether they got hit with a mesovortex or "Fist of God" gust.

There's some idiot on another weather forum STILL insisting that this (and Michael) were no more than Cat. 3, and still has not been banned. I believe I will no longer be frequenting that forum for tropical cyclone discussion.

[JtSmarts]

 https://twitter.com/RMS/status/1168943079249891328

[ronjon]

Unreal. They got completely destroyed.

https://www.facebook.com/wxchasing/vide ... 142664492/

Complete utter devastation - many homes completely leveled off their foundations.

[Michele B]

https://twitter.com/TravisCC/status/1168935463526309892

Every time I go to say "that looks like tornado damage!" I remind myself that Dorian was as strong as an F3 tornado (158–206 mph), but lasted for almost an entire day. So no surprise that many buildings are stripped to the slab, really.

Horrifying.

Exactly right. A hurricane is like a TORNADO, only much, much larger, and moving much, MUCH, MUCH slower. So more damage.

I would imagine a Cat 2-3 is like an EF1, whereas this monster, Cat 5 was like an EF3. Never experienced an EF3, living in SWFL, and I never want to, but I guess it's the same thing. Only a tornado is over in minutes, altho a hurricane can last for hours - well, DAYS, in this case.

Maybe if people were to see it with that perspective, they'd take them more seriously.

I get tired of hearing poeple say, "Cat 1? Pffft. Call me when it gets SERIOUS."

[CronkPSU]

if the storm is getting stronger and the center re-tightening back up, does that mean the wind field will decrease again as it tightens back up?

[aperson]

I just don't see a strengthening system here atm like other people are reporting. Its eye keeps growing as it sheds its angular momentum out into rainbands. It keeps entraining dry air and opening its eye. MIMIC-TPW2 is showing much drier air than yesterday being entrained from its west. It continues to have stacked vorts all the way up to 200mb with excellent lower convergence and strong upper divergence in its anticyclone, but it cannot get the fuel to pump itself back up.

It's already broadened and flattened its wind field out to such a degree that it's not going to instantly ramp back up once conditions are more favorable like those small compact-core systems. I really agree with the previous posters that mentioned that this system reminds them of Ike.

[plasticup]

if the storm is getting stronger and the center re-tightening back up, does that mean the wind field will decrease again as it tightens back up?

Usually not to any significant degree.

[ScottNAtlanta]

It looks like a rather large eye is trying to clear out

I see that too on this vis loop: https://www.tropicaltidbits.com/sat/sat ... t=vis-swir

Actually, even easier seen here on this BD curve https://www.tropicaltidbits.com/sat/sat ... =ir-dvorak
Certainly clearing out a bit. Can't say i'm seeing much motion with any westward component. 'Course, I can't swear that i'm seeing much motion period LOL. Looks like a northward drift to me

Thats what it looks like to me...more northward than anything...and not very fast at all

[Hypercane_Kyle]

FYI -- 185mph winds is solid EF4 range. Abaco experienced the equivalent of an EF4 tornado for hours compounded by horrific storm surge. I don't think we've ever seen a hurricane this destructive before.

[ScottNAtlanta]

FYI -- 185mph winds is solid EF4 range. Abaco experienced an EF4 tornado for hours.

more like days

[toad strangler]

After not worrying that much the last few days and liking the east trends, the 12Z Euro is kind of worrying me for even here in the SAV area. It comes within 75 miles of SAV now and is getting closer to a Matthew type track. Matthew was about 35 miles from SAV and ~20 miles offshore. It had been as much as 150 miles away yesterday. I didn't expect this shift and hope it goes back.

Was hoping I wouldn't have to use my well inland hotel reservations. Now my hope is lowered somewhat and glad I held into them.

I wonder if his weakening has brought the steering so low that it has gained a sig westerly component vs the higher steering layers.

I'm about 15 miles inland and yesterday's 18Z and today's 0Z Euro had only 2.5" of rain here. The 6Z had 3" and this 12Z run suddenly has 9"!
Earlier Euro runs had only TD type winds. But the 12Z run has solid TS force winds. Not a good trend but hopefully this ends up just a scare and it trends back the other way!!

Because of the geographic advantage of GA vs most of SC, they put GA only in a TS warning whereas to the north and south it is an H warning. If this 12Z Euro trend continues, they may very put GA in an H warning. GA is in a H watch now.

I don’t run from hurricanes knowing I’m nowhere near a surge or flood zone. I’m 8 miles inland. The only time I’d think of taking off is if a situation like what just happened in N Bahamas was possible. Everybody has their own threshold and variables to consider. It would probably make for a very interesting stand alone topic.

[TheDreamTraveler]

if the storm is getting stronger and the center re-tightening back up, does that mean the wind field will decrease again as it tightens back up?

Wind field won't decrease unless it really weakens. It'll keep getting bigger once it gets farther north and starts to transition to extratropical. But by then the core winds at the center won't be as strong since they're not as tightly wound.

[Michele B]

It looks like just about every wooden home in Abaco is gone.
I am still shocked how many homes were built with wood in the Bahamas, I know they are the cheapest way to go, but they are definitely the cheapest way to go in the long run if you want to still have a home after a Major Hurricane.
In Cuba every new home during the past 70 years or so had to be built with reinforced concrete, even the roof.

there was a shantytown in the Marsh Harbour area home to Haitian immigrants, that appears to have been obliterated.

I hope all those poeple evacuated....

[caneman]

It's good to take a couple hour break. Sometimes your eyes can deceive. A couple hours later it does looks NW

[drewschmaltz]

It looks like just about every wooden home in Abaco is gone.
I am still shocked how many homes were built with wood in the Bahamas, I know they are the cheapest way to go, but they are definitely the cheapest way to go in the long run if you want to still have a home after a Major Hurricane.
In Cuba every new home during the past 70 years or so had to be built with reinforced concrete, even the roof.

there was a shantytown in the Marsh Harbour area home to Haitian immigrants, that appears to have been obliterated.

I hope all those poeple evacuated....

to where?

[hurricaneCW]

https://twitter.com/TravisCC/status/1168935463526309892

Every time I go to say "that looks like tornado damage!" I remind myself that Dorian was as strong as an F3 tornado (158–206 mph), but lasted for almost an entire day. So no surprise that many buildings are stripped to the slab, really.

Horrifying.

Exactly right. A hurricane is like a TORNADO, only much, much larger, and moving much, MUCH, MUCH slower. So more damage.

I would imagine a Cat 2-3 is like an EF1, whereas this monster, Cat 5 was like an EF3. Never experienced an EF3, living in SWFL, and I never want to, but I guess it's the same thing. Only a tornado is over in minutes, altho a hurricane can last for hours - well, DAYS, in this case.

Maybe if people were to see it with that perspective, they'd take them more seriously.

I get tired of hearing poeple say, "Cat 1? Pffft. Call me when it gets SERIOUS."

The extreme pressure differentials (rises/falls) and rapid wind shifts are far more severe in a tornado, so how the winds affect structures is not the same.

Even an EF-1 tornado can be more severe, wind wise, than a Cat 3 or even Cat 4 hurricane but a tornado is very concentrated whereas a hurricane covers hundreds of miles not to mention the biggest impacts, inland flooding & surge.

In Dorian's case though, the wind impacts look like an EF-3 (he was 185mph at LF) but I'm sure it's a combo of wind/surge/rain that all work together to weaken structures.

[aperson]

if the storm is getting stronger and the center re-tightening back up, does that mean the wind field will decrease again as it tightens back up?

Wind field won't decrease unless it really weakens. It'll keep getting bigger once it gets farther north and starts to transition to extratropical. But by then the core winds at the center won't be as strong since they're not as tightly wound.

Excellent point. It's real important to bear in mind that as it gains latitude the increase in Coriolis force is going to result in wind fields broadening as a tropical cyclone moves poleward with all other factors held constant.

[Michele B]

https://twitter.com/TravisCC/status/1168935463526309892

Every time I go to say "that looks like tornado damage!" I remind myself that Dorian was as strong as an F3 tornado (158–206 mph), but lasted for almost an entire day. So no surprise that many buildings are stripped to the slab, really.

Horrifying.

Not really. Hurricane winds and torandic winds are not the same, and comparing them directly is inadvisable. FWIW you're also using the old Fujita scale -- 185mph winds on the new scale would be high end EF4.

In what ways is it wrong to compare hurricane and tornadic winds? How are they different?

Serious question.

[aperson]

Every time I go to say "that looks like tornado damage!" I remind myself that Dorian was as strong as an F3 tornado (158–206 mph), but lasted for almost an entire day. So no surprise that many buildings are stripped to the slab, really.

Horrifying.

Not really. Hurricane winds and torandic winds are not the same, and comparing them directly is inadvisable. FWIW you're also using the old Fujita scale -- 185mph winds on the new scale would be high end EF4.

In what ways is it wrong to compare hurricane and tornadic winds? How are they different?

Serious question.

Tornadic winds are shorter duration and are much more turbulent. Winds in a mature hurricane are typically more geostrophically balanced so there is less short-term turbulence but more long-term constant wind from a uniform direction.

There is much more to wind than just its speed.

[CronkPSU]

no changes at 3PM


3:00 PM EDT Tue Sep 3
Location: 27.6°N 78.7°W
Moving: NW at 5 mph
Min pressure: 959 mb
Max sustained: 110 mph