Severe WX April 11th-13th, 2020 Severe Weather Threat

[Kory]

I know some of you care about this stuff - ABC 33/40 has posted James Spann's wall to wall coverage from Sunday night on Youtube

The best in the business.

On another note, does he ever eat or go to the bathroom during this coverage? I never seen him step away for even a minute.

 

[Shakespeare2016]

Well I think the range of the EF-4 category should exceed 200 mph for sure.

This is just a guess and I am no engineer.
EF0: < 80 mph
EF1: 81-110 mph
EF2: 111-145 mph
EF3: 146-184 mph
EF4: 185-229 mph
EF5: 230+ mph

 

[vanni9283]

This is just a guess and I am no engineer.
EF0: < 80 mph
EF1: 81-110 mph
EF2: 111-145 mph
EF3: 146-184 mph
EF4: 185-229 mph
EF5: 230+ mph

Pretty legit to me!

Here's my calculations:
EF0: 69-97 mph
EF1: 98-126 mph
EF2: 127-155 mph
EF3: 155-189 mph
EF4: 190-230 mph
EF5: >230 mph
I just basically took the wind values of the current EF-scale and made them knots instead of mph. This is what their values would be as mph.
I do think the low end is a little high though.

 

[buckeye05]

But again, what was the structural integrity of it?

No way of telling much from an aerial shot. It IS a poured slab foundation house, which if finished with anchor bolts is the strongest foundation type. No way of telling without closeups though.

 

[vanni9283]

No way of telling much from an aerial shot. It IS a poured slab foundation house, which if finished with anchor bolts is the strongest foundation type. No way of telling without closeups though.

I'm sure more pictures will come. But contextually, the fact that there's nothing left standing around it suggests to me a super high DI.

 

[Shakespeare2016]

This is one of the largest moderate risk tornado outbreaks I have ever heard of. Two other moderate risk outbreaks I know of that over performed was March 13, 1990 and June 17, 2010. There are probably at least a few more.

 

[andyhb]

This is one of the largest moderate risk tornado outbreaks I have ever heard of. Two other moderate risk outbreaks I know of that over performed was March 13, 1990 and June 17, 2010. There are probably at least a few more.

4/15/11 was a big one.

 

[Equus]

Big lesson with this is this was a massive scale outbreak even without the S MS monsters. Imperfect storm mode didn't matter much; MCV comma heads, linear bands, and embedded supercells in QLCS complexes dropped dozens of tornadoes including a dozen or more strong. When you got parameters this extreme, the atmosphere will usually find a way to put down tornadoes as long as there's convection

 

[Shakespeare2016]

4/15/11 was a big one.

March 13, 1990 had 59 confirmed tornadoes. Two were F4 and two were F5.
June 17, 2010 had 75 confirmed tornadoes with 4 EF4's.
April 14, 2011 had 46 tornadoes with one EF3 and April 15, 2011 had 78 tornadoes with 5 EF3's.
April 12, 2020: has had 44 so far with one EF4.

 

[brianc33710]

March 13, 1990 had 59 confirmed tornadoes. Two were F4 and two were F5.
June 17, 2010 had 75 confirmed tornadoes with 4 EF4's.
April 14, 2011 had 46 tornadoes with one EF3 and April 15, 2011 had 78 tornadoes with 5 EF3's.
April 12, 2020: has had 44 so far with one EF4.

The only things the 14-5 Apr 11 outbreak lacked was an EF-4/5 and I guess a few more EF-3s. It had everything else.

 

[Shakespeare2016]

The only things the 14-5 Apr 11 outbreak lacked was an EF-4/5 and I guess a few more EF-3s. It had everything else.

Another thing about this recent tornado outbreak the two monster tornadoes damage looks as strong or possibly stronger than the damage from Hesston and Gossell F5 tornadoes from March 13, 1990.

 

[Weatherphreak]

I said it earlier but there is nothing worse than embedded supercells in a QLCS. Majority of the tornadoes were violent spin ups. Also seems like there was something that really set the storms off and force the warm front farther north around 6pm. That’s when you had the Boaz, sand mountain, and Trenton/Nooga tornadoes which persisted throughout the line as the line marched East. I can’t imagine what this would have looked like if the warm fron advances farther north earlier and you had a bigger area with discrete supercells rolling through.

 

[brianc33710]

After S AL underperformed Sunday night, I went to bed thinking that the SPC had made the right decision to hold off on the High Risk. After a couple of days now there were many parts of the SE definitely should have had the upgrade. But I don't think much of GA, TN, & N/SC were even in the moderate zone. Did the SPC ever expand the moderate far enough N & E to cover those multiple GA/TN/SC/NC EF-2-3s?

 

[Brice]

After S AL underperformed Sunday night, I went to bed thinking that the SPC had made the right decision to hold off on the High Risk. After a couple of days now there were many parts of the SE definitely should have had the upgrade. But I don't think much of GA, TN, & N/SC were even in the moderate zone. Did the SPC ever expand the moderate far enough N & E to cover those multiple GA/TN/SC/NC EF-2-3s?

No, TN had a sliver in the MDT risk, once the second SPC outlook came on the day of the outbreak, extreme eastern GA was in the moderate risk. S/NC were in a marginal and slight risk

 

[andyhb]

This is just outrageous.

 

[Timhsv]

OK, I still haven't seen a post storm assessment from the suspected EF4/EF5 from Sunday as of yet? Have I missed it or is KJAN still doing the assessment?

 

[SilentShadow87]

4/15/11 was a big one.

6/17/10 was another one. 15 strong tornadoes, 4 violent. In hindsight that would absolutely have warranted a high risk in my books.

 

[South AL Wx]

NWS LIX posted this on Facebook:

WFO LIX sent someone back up to Walthall County, MS to further assess the damage from Sunday's tornado. We are in consultation with engineers and tornado forensic experts to assist in the survey assessment to assure the most appropriate rating. Still under review.​

 

[Shakespeare2016]

The EF4 tornado in JAN area was more than 2 miles wide per twitter.

 

[vanni9283]

Is that the final rating? Or is NWS LIX still assessing the path?