Severe WX December 10 & 11, 2021 Severe Threat

[buckeye05]

Ignoring that particular slab for a second, the way it stumped that tree nearby is incredible, especially since it was relatively out in the open.

Regardless of construction, the contextual evidence speaks volumes, no doubt about it.

 

[OHWX97]

I hope it did save lives last night, but encouraging people to evacuate in advance of an approaching tornado, especially in heavily populated areas, is way too risky. I can't forget about how close Oklahoma City came to having an epic disaster on May 31, 2013 because a certain TV meteorologist ordered hordes of viewers to evacuate south, and the traffic jam that resulted.

 

[CheeselandSkies]

I hope it did save lives last night, but encouraging people to evacuate in advance of an approaching tornado, especially in heavily populated areas, is way too risky. I can't forget about how close Oklahoma City came to having an epic disaster on May 31, 2013 because a certain TV meteorologist ordered hordes of viewers to evacuate south, and the traffic jam that resulted.

Um, what? You're not supposed to evacuate from a tornado (unless you're in a mobile home). Least of all one moving 50-60 MPH, in the dark.

 

[locomusic01]

I hope it did save lives last night, but encouraging people to evacuate in advance of an approaching tornado, especially in heavily populated areas, is way too risky. I can't forget about how close Oklahoma City came to having an epic disaster on May 31, 2013 because a certain TV meteorologist ordered hordes of viewers to evacuate south, and the traffic jam that resulted.

Very curious what "evacuations" entailed in this case. Like, if we're talking people heading to designated shelters well in advance of a storm or something I totally get it. If not, yikes.

 

[CheeselandSkies]

Very curious what "evacuations" entailed in this case. Like, if we're talking people heading to designated shelters well in advance of a storm or something I totally get it. If not, yikes.

Exactly.

 

[buckeye05]

Evacuation is a tricky call to make, and one that has to be made quickly and strategically. In situations where there’s a very clear and consistent path, an easily accessible escape route that dives due south or north with little traffic, and a violent tornado imminent, it can be worth it. I made this call with the Dayton EF4, and would do it again should a similar situation arise.

 

[Liberty4dayz]

I don't think that tornado struck many towns directly, thankfully. It kind of grazed Monette and Leachville and then spent a long time over sparsely populated areas before splitting the uprights between Hayti and Caruthersville. At least that's what I'm hoping given the relative lack of damage photos coming out of there.

Here what's left of my nephew's home on Stateline RD (county Rd 655 I believe.) Southeast of Hornersville. Extremely lucky this thing missed that town. Only like 800 people there, it's where my wife is from. It would have been blown down, never rebuilt. I'm sure of it. Crazy it left the door standing.

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[TornadoFan]

EF-3 damage found so far.

 

[OHWX97]

Evacuation is a tricky call to make, and one that has to be made quickly and strategically. In situations where there’s a very clear and consistent path, an easily accessible escape route that dives due south or north with little traffic, and a violent tornado imminent, it can be worth it. I made this call with the Dayton EF4, and would do it again should a similar situation arise.

There are certainly situations were evacuation is essential for survival and I'm glad you were easily able to make it to safety, but would you feel the same way if the Dayton metro were evacuating en masse? I'm concerned that the idea of evacuating ahead of a tornado catches on to the point where not only does it become unproductive, but a massive hazard in and of itself. It's an incredibly tricky subject.

 

[TH2002]

Ignoring the foundation on the right, there is this large foundation:

Assuming it was a well anchored home, it could very well be EF5 damage. Hence lies the problem with trying to rate a tornado based on a single aerial photo. Regardless of whether it was a well anchored home or not, the wind rowing/ground scouring is pretty incredible.

 

[buckeye05]

There are certainly situations were evacuation is essential for survival and I'm glad you were easily able to make it to safety, but would you feel the same way if the Dayton metro were evacuating en masse? I'm concerned that the idea of evacuating ahead of a tornado catches on to the point where not only does it become unproductive, but and massive hazard in and of itself. It's an incredibly tricky subject.

Yeah if there’s even a chance of hitting a traffic jam, then it’s a terrible idea. But when I did it, I-675 was about as empty as I have ever seen it. Everyone was either asleep or sheltering in their homes. The Dayton metro hadn’t been hit by an EF3+ since 1969 (I don’t count Xenia), so I think evacuating wasn’t even an option that crossed anyone’s mind.

 

[atrainguy]

Ignoring the foundation on the right, there is this large foundation:
View attachment 10948
Assuming it was a well anchored home, it could very well be EF5 damage. Hence lies the problem with trying to rate a tornado based on a single aerial photo. Regardless of whether it was a well anchored home or not, the wind rowing/ground scouring is pretty incredible.

I believe this is the property on Google Maps. If so, it kinda looks like the second foundation is a pole barn or garage. Not sure if that necessarily changes anything rating-wise, I'm pretty ignorant when it comes to different kinds of structures and the EF ratings.

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.com

 

[Evan]

So much intensity, skepticism, weirdness, and focus on whether or not a tornado will be rated EF-5 should be proof enough there's definite issues with the current ratings process. JMO.

 

[buckeye05]

I believe this is the property on Google Maps. If so, it kinda looks like the second foundation is a pole barn or garage. Not sure if that necessarily changes anything rating-wise, I'm pretty ignorant when it comes to different kinds of structures and the EF ratings.

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.com

Yeah was just about to say, that looks like a garage or outbuilding slab. That means the highest possible rating that could be applied there would be EF2.

 

[Jacob]

Yeah if there’s even a chance of hitting a traffic jam, then it’s a terrible idea. But when I did it, I-675 was about as empty as I have ever seen it. Everyone was either asleep or sheltering in their homes. The Dayton metro hadn’t been hit by an EF3+ since 1969 (I don’t count Xenia), so I think evacuating wasn’t even an option that crossed anyone’s mind.

Given ample time, it can be an easy call if traffic isn’t an issue and you know what you are doing. Similar to you, I’ve made that decision before. I was a student at Alabama on April 27, and I left my
3rd floor apartment about 25 minutes before it came
through and drove south and out of the path of it (it missed my apartment complex by about 1/4 mile).

But I agree with others that suggesting any type of evacuation outside of a very small group such as chasers and weather nerds is a recipe for disaster.

 

[Fred Gossage]

A lesson to be taken away forecasting wise: never trust the models to handle surface winds well when a deepening surface low is depicted.

Here's the NAM 0-1 km SRH, valid for 18z 4/27/2011. This was only 42 hours out. Values of 200+ were confined to areas north of Highway 278 in Alabama and did not reach 300 anywhere in Alabama. We know what kind of low-level shear was in place by midday and early afternoon. This is a common occurrence in all the models, even the CAMs. They do not properly model the isallobaric response in the lowest-level winds in the presence of pressure falls. If a surface low hasn't passed your longitude, it isn't occluded, and pressures are falling, every single model in this solar system will usually underdo the backing of the surface wind, at least a little.

This was also a good lesson in the fact that the models, even the highest-resolution CAMs in even the 0-3 hr out timeframe, are significantly underdoing surface thermals in these strong WAA regimes and with even a little insolation. This also shows that even the CAMs are incorrectly decoupling the boundary layer right at sunset, and if it's a setup with strong low-level winds and quality dewpoints, temperatures will not cool significantly after dark. If we have strong low-level winds and dewpoints up in the 60s, especially the mid 60s... if temperatures are in the 70s before dark, they probably won't cool after dark, AND if the area is in the 60s before sunset with 70s just upstream, those 70s will probably be advected in after dark. We have to keep this in mind going forward for even the daytime events, but especially the overnight and morning events. It was actually the FV3 that more correctly modeled the thermals in the warm sector and the evolution and higher-end nature of the supercells with this event, especially once we got within 24 hrs, by still keeping UH tracks into the TN Valley, but backing off on their intensity and focusing north with the violent looking activity.

The biggest refresher this gives on the forecast desk is that trough amplitude is more important than trough tilt. Yes, meridional type positive tilt troughs are unfavorable for significant severe weather (not impossible though, ask Arkansas on March 1 1997). But a lower amplitude trough of any tilt has a forcing regime and large scale ascent spread out over the warm sector in a way that is favorable for sustaining discrete, long-tracked storms should the other parameters be in place.

 

[TornadoFan]

The Amazon warehouse in Illinois.

 

[Tennie]

Well, I went to bed around 11:00 PM last night (finally deciding to just head for bed and check the news reports the next day). Then at around 3:00 AM I was awoken by the tornado warnings that had been issued for Nashville. The tornado that prompted the warnings passed between my house and the OHX radar site (the former by a considerable distance, fortunately), so around 4:00 AM I headed back to bed. I was apparently so exhausted that I ended up sleeping until around noon. At one point during the early morning storms I called some neighbors of ours to let them know what was going on; I later received some texts from them thanking me for giving them the head's-up.

What particularly shocked me to learn about was the Bowling Green storm. I was born in Bowling Green and have several relatives who live around there; in addition, I spent six years (2008-2014) at WKU. As such, my heart goes out to the people of Warren County, Kentucky.

 

[Bamamuscle]

So much intensity, skepticism, weirdness, and focus on whether or not a tornado will be rated EF-5 should be proof enough there's definite issues with the current ratings process. JMO.

I think it’s pointless. A pseudoscientific process.


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[Evan]

Given ample time, it can be an easy call if traffic isn’t an issue and you know what you are doing. Similar to you, I’ve made that decision before. I was a student at Alabama on April 27, and I left my
3rd floor apartment about 25 minutes before it came
through and drove south and out of the path of it (it missed my apartment complex by about 1/4 mile).

But I agree with others that suggesting any type of evacuation outside of a very small group such as chasers and weather nerds is a recipe for disaster.

Hopefully community shelters will become ubiquitous and personal ones will become more affordable.

I can absolutely see taking myself and my family to the new community shelter located 2.9 miles away if it's a day with strong potential and there's a confirmed tornado 30+ minutes away.

If I was staring down a monster like the storms on 4/27 or last night, heck yeah, I'd "evacuate" like you two mention. But I've also intercepted a number of tornadoes before and used to chase frequently. It would be a last ditch effort. Don't know how much I trust our community shelter just yet. Construction isn't quite finished yet but when it is I'm going to go check it out and see if the GC did good work.