ATL: MICHAEL - Post-Tropical - Discussion

[CrazyC83]

^
Curious to see the severe thunderstorm warnings posted along with the tropical storm warnings...the warnings are all around the circulation as it's pushing toward the coast. I guess we see why.

They don't usually use SVR warnings concurrent with TS warnings, even though they are for different situations (SVR is convective for individual cells or lines, TSW is gradient/system-based).

[PandaCitrus]

Major destruction to Bay Medical Center where they had to evacuate all the patients. I'd be very interesting in the post analysis to see the wind field and what the winds were in the western eyewall that hit Panama City.

 https://twitter.com/DanielWGXA/status/1050399976470261760

[CrazyC83]

Why does the NWS issue a severe thunderstorm warning for winds up to 60mph when said area is already under a TS warning which technically covers winds up to 64kt?

I think it's a combo of these winds relating more to mixing of cold and dry air downward instead of from the pressure gradient of the TS. Plus it's impacting a major population center during rush hour so the extra warning was probably good. Radio and TV would break in for the new thunderstorm warning but not for the continuing tropical storm warning. Also I just lost power and I was only on the edge with 30 to 40 mph gusts.

I think they should pick one and go with it. It's redundant. They could have easily have issued a special weather statement about the incoming winds (which have already been warned for with a TS warning) or they could have dumped the tropical headlines in favor of a high wind warning...which could have been more time specific wrt timing

Given the fact wind gusts are 60-70 mph at their peak, it calls for a warning. But this is definitely a grey area. A High Wind Warning would mean that the gradient of the system is producing severe winds. A Severe Thunderstorm Warning would be for the individual cells or lines, and in this case there is definitely a convective setup of Michael, almost behaving like a squall line. A Tropical Storm Warning would be for the combined impact of a tropical storm, but is typically seen as a longer duration warning (like a HWW). In a short-fuse situation, the thought of a SVR may be warranted, even if redundant from an impact perspective. Have there been severe winds reported, outside of the immediate coast, from the general circulation and not just from the pseudo-squall line? (BTW, I would consider Michael as extratropical now personally)

As for a Special Weather Statement, who pays attention to them?

[nascarfan999]

Personally I believe there is strong enough evidence for an upgrade to cat 5 with the most detailed case laid out by one of our pros late last night several pages back. That said, one thing I want to point out is to keep in mind that the destruction several posters today have referred to as their reason for an upgrade is the damage in Mexico Beach. However, I would argue that a lot of the "total destruction" that is there was due to the surge as much if not more than the wind.

[johngaltfla]

Personally I believe there is strong enough evidence for an upgrade to cat 5 with the most detailed case laid out by one of our pros late last night several pages back. That said, one thing I want to point out is to keep in mind that the destruction several posters today have referred to as their reason for an upgrade is the damage in Mexico Beach. However, I would argue that a lot of the "total destruction" that is there was due to the surge as much if not more than the wind.

Have no fear. The NHC has the winter to review REAMS of computer data and obs to determine this. In the end, if the facts justify it an upgrade will occur.

[PandaCitrus]

Do any of the pro mets have an estimate on what the actual surge was in Mexico Beach? I believe the NHC predicted up to 14 feet. Is 14 feet indicative of the damage shown or could it be higher? I think the Cat 5 SLOSH maps go up to 18 or 19 feet in this area.

[CrazyC83]

Do any of the pro mets have an estimate on what the actual surge was in Mexico Beach? I believe the NHC predicted up to 14 feet. Is 14 feet indicative of the damage shown or could it be higher? I think the Cat 5 SLOSH maps go up to 18 or 19 feet in this area.

I'm not sure how high it was right at the beach, but in town from Ginger Zee's videos it looked like about 7 to 10 feet of water. It may have been higher in spots, so the 14 feet may have verified.

[USTropics]

Do any of the pro mets have an estimate on what the actual surge was in Mexico Beach? I believe the NHC predicted up to 14 feet. Is 14 feet indicative of the damage shown or could it be higher? I think the Cat 5 SLOSH maps go up to 18 or 19 feet in this area.

We'll probably have to wait for aerial footage (NASA does before/after shots typically a few days after landfall). The surge debris line should be discernible (the farthest extent of the surge will have a line of debris). Measuring distance from coast to surge debris line will give a rough estimate of surge height. This will be used in the reanalysis for sure.

[supercane4867]

Donalsonville airport in SW GA, located about 120miles inland, measured a wind gust of 115mph last night

[northjaxpro]

That is mindblowing how Michael's eyewall stayed intact that far inland and just how powerful he was last evening.

Just incredible!

[supercane4867]

Personally I believe there is strong enough evidence for an upgrade to cat 5 with the most detailed case laid out by one of our pros late last night several pages back. That said, one thing I want to point out is to keep in mind that the destruction several posters today have referred to as their reason for an upgrade is the damage in Mexico Beach. However, I would argue that a lot of the "total destruction" that is there was due to the surge as much if not more than the wind.

Surge arrives before the strongest winds come ashore. Most structues near the coast were likely already under water when the eyewall came through, thus water can actually "protect" buildings from extreme wind damage, if they had not already fallen apart in the momentum of water. It's quite hard to differentiate wind damage and surge damage in Mexico Beach. That said, wind damage in Panama City is still one of the most impressive I've ever seen,especially since they are caused by the NW eyewall with wind direction coming from the inland side.

[BobHarlem]

 https://twitter.com/PowerOutage_us/status/1050541614446325760

[Hypercane_Kyle]

The scale and severity of the wind damage is pretty incredible. I think Michael was closer to ~160-170mph at landfall. Some of the damage looks like what happened on Joplin in 2011 and OKC in 2013.

[Chris_in_Tampa]

 https://twitter.com/NWSWPC/status/1050518980925030400




Higher quality:

[NDG]

On my way down to S FL this evening there were a lot power co trucks heading south, wonder why.
I also saw a storm chaser returning back to S FL, had an older model 4 runner.

[Abdullah]

https://twitter.com/PowerOutage_us/status/1050541614446325760

What's up with South Carolina?

[nutkin517]

What I wonder is why there is so much debris at Mexico Beach? If you look at pictures of Cameron after Hurricane Rita or High Island after Hurricane Ike, it is basically like the ground was scraped clean for the most part. Is this because of a difference in building codes? Or just more structures in the area?

[Hammy]

What I wonder is why there is so much debris at Mexico Beach? If you look at pictures of Cameron after Hurricane Rita or High Island after Hurricane Ike, it is basically like the ground was scraped clean for the most part. Is this because of a difference in building codes? Or just more structures in the area?

I think it's because there was significantly more wind damage this go, so more things blowing around on top of the stuff under the water.

[p1nheadlarry]

What I wonder is why there is so much debris at Mexico Beach? If you look at pictures of Cameron after Hurricane Rita or High Island after Hurricane Ike, it is basically like the ground was scraped clean for the most part. Is this because of a difference in building codes? Or just more structures in the area?

Michael probably ripped a lot of the structures apart with wind before the water took over.

[Chris_in_Tampa]

In regard to surge, the NHC said this earlier. It's an estimate based on currently available information.

 https://twitter.com/NHC_Surge/status/1050409595594842113