2011-04-27 MISC: AL,TN,MS,KY,OH,IN,WV,GA

[Craig Norris]

this link provides better insight on the debate over the EF5 rating on some of these tornadoes. While one would have to assume that there were periods of EF5 intensity, I had not seen any good photos comparable to the damage in the 91 Andover and 07 Greensburg tornadoes.

 

[Warren Faidley]

RE: "Amateur chasers killed."

Let's hope this is just a rumor. I had a media inquiry from CNN early this morning concerning the same information. I would imagine if it was true, word from families or friends would have already surfaced. I just heard a similar rumor, but they were "looters" not chasers.

W.

 

[George Dikun]

If that story about the amateur chaser deaths is true, it would be the first time a storm chaser has died while on the chase, right? And the footage they got must be terrifying and awe-inspiring, if it survived. Who knows, maybe their footage can be beneficial to science.

 

[Trey Thee]

this link provides better insight on the debate over the EF5 rating on some of these tornadoes. While one would have to assume that there were periods of EF5 intensity, I had not seen any good photos comparable to the damage in the 91 Andover and 07 Greensburg tornadoes.

Yeah, I agree. I have not seen anything yet that puts these tor's on par with Greensburg, May 3 1999, and other F5/EF5 type storms. Doesn't mean they aren't EF5's. Another issue at hand is the type of construction involved as i mentioned several pages back. That can make a substantial difference in the visual damage. As we all know, its one thing to blow a trailer to bits, its quite another to take a full frame on slab home thats anchored to the foundation and blow it into thousands of pieces.

It will be interesting to see how this shakes out. The number of EF4's is simply mind boggling though. Does anyone know the most EF4's in a day and in a single outbreak? You'd think this would have to rival the biggest outbreaks of the past?

 

[Andrew de la Garza]

this link provides better insight on the debate over the EF5 rating on some of these tornadoes. While one would have to assume that there were periods of EF5 intensity, I had not seen any good photos comparable to the damage in the 91 Andover and 07 Greensburg tornadoes.

This picture (from FOX News) is the most impressive piece of evidence I have seen so far.

There's also the shredded railroad bridge from the Tuscaloosa overflight video...

Edit: To clarify, that picture is apparently from Mississippi, so it may have come from the one tornado that has already been officially rated as EF-5.

 

[Trey Thee]

This picture (from FOX News) is the most impressive piece of evidence I have seen so far.

There's also the shredded railroad bridge from the Tuscaloosa overflight video...

That's a good pic, I also so one additional pic yesterday, CNN maybe? That had a bunch of trees snapped off at about 12 feet in height and some of the bark stripped off. This fox pic and that one rank up there pretty high. That is some impressive damage.

 

[Trey Thee]

Here's a few pictures I dug up on google for comparison
Greensburg

May 3 1999

Andover

Difficutl finding fairly large damage pics of Andover...

 

[Craig Norris]

One thing that really bothers me, all these guys say they've been doing this for 30 years and never seen anything like it. Yet Greensburg was a mile + wide with devastating destruction...

OKC had higher wind speeds varied in width from .5 to 2 miles and impacted a more significant metro. They seem to have a memory thats about 6 mos long. Not to mention as others have the South gets hit with significant tornadoes ever year, not in this volume, but they have one or two major tor's a year.

These storms were significant and violent and the number of EF3+ tor's appears to be almost unheard of. But any particular tor could easily be compared with other storms over the last 20 years.

while it was "just" categorized an F-4, the 2004 Hallam NE wedge was also a monster...possible wider than any of the above mentioned F/EF5's.

 

[Brandon Jenkins]

Difficutl finding fairly large damage pics of Andover...

Here is a video containing the Andover aftermath shot by a resident (who also happened to shoot the tornado coming directly at them just prior). I know some of the images coming out of Pleasant Grove looked pretty bad, but at this point it is all speculation.

http://www.youtube.com/watch?v=5yjd8l9WJHQ

First part of the above video for those that haven't seen it: http://www.youtube.com/watch?v=ue7eI1V-7wo&feature=watch_response

 

[Trey Thee]

This picture (from FOX News) is the most impressive piece of evidence I have seen so far.

There's also the shredded railroad bridge from the Tuscaloosa overflight video...

Edit: To clarify, that picture is apparently from Mississippi, so it may have come from the one tornado that has already been officially rated as EF-5.

That railroad bridge was decimated and scattered like matchsticks.

 

[mwenzbauer]

The number of EF4's is simply mind boggling though. Does anyone know the most EF4's in a day and in a single outbreak?

Not 100% certain but 4/3/74 had I believe 24 F4 tornadoes, Palm Sunday '65 I think had 17 (not sure one or two of those shouldn't have been F5)... the number of voilent tornadoes from this outbreak will dwarf anything since the Super Outbreak, I could see 3-5 of these being rated EF5.

Interesting discussion on the max tornado damage, i.e. not seeing damage as severe as OKC '99 or Greensburg... I'd rank Jarrell or Guin ahead of either OKC or Greensburg, in fact I thought the max damage photos from Parkersburg may have been worse than Greensburg. Then again, i'm sure there are a lot of members on here who know a lot more on the subject than I do so I would certainly defer to them or love to hear their input.

 

[Derek Weston]

Hopefully, the NWS will produce a comprehensive analysis of the meteorology of this event. Just looking back at the archived mesoscale analysis at 18z on 4/27, the following can be noted:

1. Distinct 500mb trough w/ base over northern Lousiana, neutral to slightly negatively tilted, and a speed max of 80 to 100 kt with divergence indicated over northwest Missssippi. It looked progressive, and was referred to as a short-wave during in the forecasts of the day, but certainly had some amplitude.

2. Very rich moisture advecting through the gulf coast states, with td's > 64 covering most of Mississippi and Alabama, and td's > 68 covering the southern 2/3's of those states.

3. Surface low of 996mb over eastern Arkansas, with attendant backed surface winds over Tennessee, and the northern halves of Mississippi and Alabama.

4. Cloud cover from ongoing convection over much of Tennessee and northern Mississippi, but significant breaks in clouds over Alabama.

5. SB CAPE of 2,000 - 3,000 j/kg over much of the southeast, with CIN eroded across about 70 percent of the area.

6. Significant Tornado Parameters of 6+ over west central Alabama up to 9 over northern Mississippi.

7. 0 - 1km SR Helicity readings of between 400-900 m2/s2 over much of Tennesee, northern Mississippi and northern Alabama.

8. Base reflectivity mosaic showing signs of 3 n/s bands of convection setting up over the outbreak area.

I know this is a quite simplified snapshot, but I would certainly appreciate any more insight from a meteorological standpoint on the setup of this outbreak.

Sounds about right. There wasn't anything terribly unique about this setup from what I can recall. Was a combination of a number of very strong parameters coming together. Think the key to the day may have been storm spacing and the isolation that was had by most supercells. I've seen some amazing parameters before "go to waste" due to the seeding of the storms and their effective competition with each other. Not the case with this outbreak.

 

[mikegeukes]

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
140 PM CDT FRI APR 29 2011

...NWS BIRMINGHAM METEOROLOGIST IN CHARGE TO PARTICIPATE IN GOVERNOR
BENTLEY'S DAMAGE SURVEY AND PRESS CONFERENCE AT 330 PM TODAY...

THERE HAVE BEEN NUMEROUS REQUESTS FOR INDIVIDUAL MEDIA TO FOLLOW NWS
TEAMS TO SURVEY DAMAGE. DUE TO THE OVERWHELMING REQUESTS...DAMAGE
AREAS THAT ARE STILL RESTRICTED...AND THE NEED FOR OUR SURVEYS TO BE
COMPLETED AS QUICKLY AS POSSIBLE...ADDRESSING AS MANY MEMBERS OF THE
PRESS AS POSSIBLE IN ONE LOCATION IS THE MOST EFFICIENT MEANS TO
MEET YOUR INFORMATION NEEDS AND ALLOWING US TO COMPLETE OUR DAMAGE
ASSESSMENTS.

METEOROLOGIST-IN-CHARGE JIM STEFKOVICH WILL ACCOMPANY GOVERNOR
BENTLEY ON HIS TOUR AT THE SCOTT ELEMENTARY SCHOOL IN PRATT CITY AT
330 PM. HE WILL BE AVAILABLE TO ANSWER QUESTIONS REGARDING THE
LATEST DAMAGE ASSESSMENT RESULTS...THE METEOROLOGY OF THE EVENT...
AND THE PROCESS AND METHODOLOGY USED TO ASSESS STORM DAMAGE
ACCURATELY.

 

[Trey Thee]

Not 100% certain but 4/3/74 had I believe 24 F4 tornadoes, Palm Sunday '65 I think had 17 (not sure one or two of those shouldn't have been F5)... the number of voilent tornadoes from this outbreak will dwarf anything since the Super Outbreak, I could see 3-5 of these being rated EF5.

Interesting discussion on the max tornado damage, i.e. not seeing damage as severe as OKC '99 or Greensburg... I'd rank Jarrell or Guin ahead of either OKC or Greensburg, in fact I thought the max damage photos from Parkersburg may have been worse than Greensburg. Then again, i'm sure there are a lot of members on here who know a lot more on the subject than I do so I would certainly defer to them or love to hear their input.

I wish my HDD hadn't crashed, I had a lot of Greensburg photos on it

Pretty decent photos too, but only 4MP.

 

[Matt Hunt]

this link provides better insight on the debate over the EF5 rating on some of these tornadoes. While one would have to assume that there were periods of EF5 intensity, I had not seen any good photos comparable to the damage in the 91 Andover and 07 Greensburg tornadoes.

Keep in mind that tornadoes are rated the highest of ALL damage along the path. So while it may only be EF5 damage for one or two houses, nonetheless it will be rated EF5. With tornadoes like Greensburg and Moore, I think those maintained EF5 intensity for a long period of time, and over a wider path. Greensburg was what, about 2 miles wide? It sounds like most of Weds tornadoes were closer to 1/2 mile wide.