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Severe WX December 10 & 11, 2021 Severe Threat

I don't know if Philadelphia would receive an EF5 today based on trenching but I hope the upcoming update to the scale provides some guidance. The fact this tornado/tornado family has done such a number of things that other tornadoes have been singularly famous for (gouging trenches/destroying a water tower/tossing loaded train cars/etc) is mind numbingly incredible
 
buckeye05 said:
The aerial photography map is not working for me right now, and I need the nearest roads to the scouring trenches so I can report them to NWS Paducah. Can anyone help me out?
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I didn't have the exact coordinates, just happened to know its general location, I'm now texting the one who sent the pic to see if he knows the location.
 
eric11 said:
The violent ground scouring sudden popped out when it crossed the TN/KY border, this is two miles north from the State border
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Sorry to nitpick, but just wanted to clarify that cycloidal marks are a distinct phenomenon from ground scouring. They're convergent lines of small, light debris (corn stalks, dirt, rocks, etc) that get deposited as the intense inflow winds reach the corner flow area of the vortex and turn vertical. Interestingly, I saw a presentation a few months ago (I think from Roger Wakimoto?) where he showed that modeling suggests these kind of markings can happen even when there aren't multiple vortices present.

Anyway, that obviously doesn't detract from the point, which is that there clearly was widespread and significant scouring as well.

Edit: I think this is the presentation if anyone's interested:

 
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locomusic01 said:
Sorry to nitpick, but just wanted to clarify that cycloidal marks are a distinct phenomenon from ground scouring. They're convergent lines of small, light debris (corn stalks, dirt, rocks, etc) that get deposited as the intense inflow winds reach the corner flow area of the vortex and turn vertical. Interestingly, I saw a presentation a few months ago (I think from Roger Wakimoto?) where he showed that modeling suggests these kind of markings can happen even when there aren't multiple vortices present.

Anyway, that obviously doesn't detract from the point, which is that there clearly was widespread and significant scouring as well.
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Very important distinction that not everyone is aware of. That kind of thing gets reported as "scouring" a lot.
 
At least so far they havent gone higher than EF3 for anything. I find it hard to believe given some of the damage that nothing has even reached EF4 for 1 or several tornadoes. But yall said theyre stingy going above a 3 so maybe thats as high as we see even if its wrong. Are WFOs under pressure not to give EF4/5s? I do remember a Carolinas tornado in the April 2011 Superoutbreak that everyone said was clearly at least a 4 but they gave it a 165 EF3 without really bothering to investigate the damage.
 
brianc33710 said:
At least so far they havent gone higher than EF3 for anything. I find it hard to believe given some of the damage that nothing has even reached EF4 for 1 or several tornadoes. But yall said theyre stingy going above a 3 so maybe thats as high as we see even if its wrong. Are WFOs under pressure not to give EF4/5s? I do remember a Carolinas tornado in the April 2011 Superoutbreak that everyone said was clearly at least a 4 but they gave it a 165 EF3 without really bothering to investigate the damage.
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One of my more wild theories is that they're trying to rub it in the faces of people like us to "prove a point" that we really don't know anything about how the EF scale works.
 
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This was the SPCs risk assessment going into Friday evening. They did a decent job overall but maybe the Mod shouldve been expanded N & E and put a Hi risk where we had the bullseye?
 
The EF scale discussion thread is a good place to rant about recent major improper scale applications but for now just interested to see what the analysis is for some of the non traditional indicators along the path like the water tower in this thread. Home damage getting EF5 is a thing of the past but incredible phenomena certainly seems to fit the bill.

Yeah the SPC outlook was very good, as always with events in the south and east they could have easily stretched the risk 200 miles to the east and verified even better since our events always want to get worse on the eastern edge of the risk area lol
 
Equus said:
The EF scale discussion thread is a good place to rant about recent major improper scale applications but for now just interested to see what the analysis is for some of the non traditional indicators along the path like the water tower in this thread. Home damage getting EF5 is a thing of the past but incredible phenomena certainly seems to fit the bill.

Yeah the SPC outlook was very good, as always with events in the south and east they could have easily stretched the risk 200 miles to the east and verified even better since our events always want to get worse on the eastern edge of the risk area lol
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I hear what you're saying, but I'm not sure I agree this is the case for every NWS office. There are some WFOs out there that I could totally see going with such a rating.
 
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