04/02/2006 DISC: IA/IL/MO/AR/TN

[Kevin Bowman]

This day warranted a MDT risk until the long track supercells got going (which were under a conditional probability at the time). I was partly expecting a high risk on the 0100 UTC (there was a hatched 15% tornado probability on that one, an upgrade from the hatched 10%), but I didn't know the specifics of what was going on. The environment in TN seemed to get more favorable after the 0100 UTC outlook for long-track tornadic supercells.

The watches were issued in a timely manner and were generally well placed. This event should have only been a MDT if we take out the supercells in AR, MO, TN (the SLGT seemed warranted with all the factors up in the air). The SPC did a good job overall yesterday, with maybe the possible exception being the 0100 UTC outlook. But then again, I didn't know all of the factors there.
[/b]

"THE COMBINATION OF MODERATE INSTABILITY AND 45-55 KT WLY MID-LEVEL
FLOW SUGGEST THE THREAT FOR A FEW SUPERCELLS AND BOWING LINE
SEGMENTS CAPABLE OF DAMAGING WINDS...LARGE HAIL AND A FEW TORNADOES.
THIS SEVERE THREAT WILL LIKELY CONTINUE SUNDAY NIGHT ACROSS THE TN
VALLEY AND NRN PORTIONS OF MS AND AL"

"A HIGH risk area suggests a major severe weather outbreak is expected, with a high concentration of severe weather reports and an enhanced likelihood of extreme severe (i.e., violent tornadoes or very damaging convective wind events occurring across a large area). In a high risk, the potential exists for 20 or more tornadoes, some possibly F2 or stronger, or an extreme derecho potentially causing widespread wind damage and higher end wind gusts (80+ mph) that may result in structural damage"

Mesoscale Discussion 405 issued at 205 had increased tornado threat if storms fired and moved into western Arkansaw.

Mesoscale Discussion 409 issued at 7 had the possibility of "long tracked significant tornadoes"

Even if th SPC had issued a high risk it wouldnt have saved lives, as was mentioned before, there was a watch and warnings. It really dosent matter that there was no PDS watch either for one, the general public usually never learns of the PDS wording anyway, most news casts only report Tornado watch till 12 ect. If anything, the high risk may have been better over illinois and indiana for the squall line not the supercells in Tennessee. The convective outlook shouldnt matter though once a watch is issued, if you are placed under a Tornado Watch, guess what, even if you are under a slight risk, you could still be hit by a tornado and it could even potentially be violent. SPC did a good job IMO.
This is from Watch 132 issued at 325

 

[Michael Auker]

I would assume that they are reporting the damage in segments if that is the case. Memphis is in charge of the Marmaduke section of the tornado track, and they haven't released anything about that as of yet.

On another note, I'm surprised that the Dyer Co. segment of damage was given only strong F3. There were a number of houses where no outer walls were present after the tornado passed. I suppose construction issues came into play when they rated these particular sites.

Gabe
[/b]

Local NWS offices aren't allowed to rate tornadoes higher than F3...only the official survey team has the authority to give F4 or F5 ratings. Apparently, the team will be visiting Arkansas, Missouri, and Tennessee in the coming days...according to another weather board. Maybe then some will be rated F4 or higher...

 

[Marc Austin]

The Dyer tornado surely looks to be F4 based on some of the aerial video. I would be very suprised to find it was rated only F3 when the state NWS officials visit the area.

 

[Rich Thompson]

Rich
Thanks for commenting on this. Outlooks aside (the general public does not care about outlooks) the watches for the most part were issued in a timely manner by the SPC yesterday with one exception. There were numerous svr and several torn warnings in TN around 3pm yesterday, long before a watch was ever issued. I was just curious if you had any input on why it took so long to get the blue box up for that area of the country yesterday? When you issue a watch, do you just look at the weather to see if it is favorable for svr or do you take into account that storms are already ongoing and severe?
Thanks for your input and hard work.
Gary
[/b]

Gary,

That's a fair question. We wrote an MD about the possibility of the small MCS in nrn MS strengthening as it moved into middle TN later in the afternoon:

http://www.spc.noaa.gov/products/md/md0404.html

The storms didn't really intensify, there was additional development NE of the small MCS. We weren't really sure how much the new development would amount to, and then I got tangled up with what I considered to be more important threats in MO/IL/AR with tornado watches 132 and 133 between 3 and 4 pm CDT. Unfortunately, we got behind the TN/KY convection, and it occurred near shift change and at the same time we had other more serious threats. The evening shift did eventually issue a SVR watch, though you can't blame them because it was ramping up as they began their shift.

Rich T.

 

[Jeff Snyder]

Hmm, from the new PNS from Memphis NWSFO, the tornado was only F3 "through" Caruthersville. That said, before it went through that town:
<div class='quotetop'>QUOTE("MEG PNS")</div>

IN MARMADUKE THE TORNADO REACHED F3 AND POSSIBLE HIGHER
INTENSITIES ALONG WITH WIDTH OF HALF A MILE TO THREE QUARTERS OF A
MILE.
...
IN CARUTHERSVILLE...PRELIMINARY ESTIMATES OF 64 INJURIES...ALTHOUGH
NO FATALITIES. AS THE TORNADO PASSED INTO THE CITY THE WIDTH OF THE
TORNADO WAS HALF TO THREE QUARTERS OF A MILE WIDE AS IT PASSED OVER
I-55. THE TORNADO HAS BEEN RATED AN F3 AS WELL. [/b]

--> http://www.srh.noaa.gov/printable.php?pil=...=20060404022151

It does sound, from the rest of the description of the tornado as it was near Marmaduke, that the tornado may have been F4. However, the sound of the PNS didn't make it seem like they think F5 is warranted. Just my interpretation.

 

[Gabe Garfield]

Local NWS offices aren't allowed to rate tornadoes higher than F3...only the official survey team has the authority to give F4 or F5 ratings. Apparently, the team will be visiting Arkansas, Missouri, and Tennessee in the coming days...according to another weather board. Maybe then some will be rated F4 or higher...
[/b]

I didn't know that was the policy...thanks for the info. So, I s'pose that's a bit like when SPC puts an unhatched probability on Day 3 for an expected severe weather outbreak because they can only go so high. It'll be interesting to see what the experts think.

Gabe

 

[Ronnie Bradley]

F2 Tornado in White County AR. PNSLZK.
[/b]

And that tornado track was roughly 1.5 miles NW and N of my residence!
Another near miss for me. The Sept 24 F2 tornado from Rita tracked 1.5 miles to the SW of my residence.
I had to work this weekend but when the supercell rolled through Nrn Searcy, I saw some funnel clouds. The F2 was beyond the horizon (trees and hills N of town...).
Baseball to softball sized hail pelted my grandparents area (Mt. Pisgah; south of Letona) and the hail did major damage to one of our churchmember's vehicle (busted windows). One person [from the Rosebud area] was in ER due to a big hailstone smashing his foot as he tried to make a run to his storm shelter. A mobile home's roof was penetrated by a big hailstone in the Center Hill area.
The LZK NWS page had a picture of the colossal hailstones, with one the size of a plastic Foldgers coffee container (5")!
While at work, someone brought in some hailstones and I held one that was easily baseball size, and I had no doubt in my mind that the said hailstone was bigger than that when it first hit the ground.

 

[John Farley]

NWS St. Louis has now upgraded the Fairview Heights, IL tornado to F2, and has confirmed a total of 4 tornadoes, 2 F2 and 2 F0. The Hillsboro, IL tornado, rated F2, was on the ground for 20 miles. The 50-60 mph movement of the storms, of course, had the effect of lengthening the tornado tracks, giving even the relatively short-lived Fairview Heights tornado a track around 7 miles long.

EDIT, Tuesday, 10:40 a.m. - Now 5 confirmed, with addition of F1 tornado near Highland, IL. Also, they are indicating a likely tornado in Randolph Co., IL, and are surveying other areas, so additional tornado tracks may be added.

Here at my house in Edwardsville, the power finally came back on this afternoon around 5:20 after being out for nearly 24 hours. It is amazing how dependent we are on electricity for so many things. We had to pitch a fair amount of food, and late this evening the grocery stores were very busy with people replentishing what had to be tossed out. Although I did not see it in the LSRs, local media reported quite a bit of straight-line wind damage around Edwardsville - 6 cars set on fire when a tree fell and dragged power lines onto them, a number of houses and apartment buildings with trees down on them, and at least one building unroofed. A number of large trees went down on a house and power lines a block or so northeast of my house.

 

[Perry Williams]

The Dyer tornado surely looks to be F4 based on some of the aerial video. I would be very suprised to find it was rated only F3 when the state NWS officials visit the area.
[/b]

I agree......IMO it was a violent tornado.

Thanks Michael for pointing that out. I knew that from the Stoughton tornado up here in WI and being around the Wx Service office in August but completely forgot about it. I'm assuming thats what the "F3 OR HIGHER" verbiage is all about. I'm sure they have their opinions. Anyone know how quickly the official survey team responds?

Breaking down what they said in their PNS for possible hints...

NUMEROUS HOUSES DESTROYED...typically associated with F3 or higher, not much light shed on the situation there.

15 RAILROAD CARS WERE LIFTED OFF THE TRACK ANDBLOWN OVER...OK let me say this right here and right now that regardless of the Fujita rating that takes an INCREDIBLE amount of force. Amazing. Now it says that F2 strength winds can push railroad cars over, but those are boxcars. I guess it also depends on the type of railroad car...and the fact it says lifted. Still doesn't shed a lot of light on the situation.

FIVE MILES EAST OF MARMADUKE...2 WELL CONSTRUCTED HOMES WERE FLATTENED AND A NEW CAR THROWN 80 YARDS...this is interesting because they used the words WELL CONSTRUCTED. Both of these things appear to fit well in the F4 description here - "Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.". Now its interesting they mentioned the distance the car flew too because typically F5 is associated with over 100m or 110 yards. Its very close and I will be intrigued by what they find.

So I'm expecting this to come up to an F4, possibly an F5...back to where we started in the quote :blink:

Anybody know if the official team will be investigating just this tornado or others as well?
[/b]

Alex, since there were over two dozen fatalities, I fully expect a NOAA Natural Disaster Survey team to conduct an extensive analysis of the entire event.

I haven't seen any images or aerial video from the Marmaduke area, but it sounds as if this violent tornado was close to F5 intensity at its peak. IMO both the Dyer and Gibson killer tornadoes were of F4 intensity (based upon video I've seen online tonight and on CNN yesterday afternoon).

 

[Terry L. Schenk]

Interesting set of parameters that existed in W TN as the storms were moving into that area. A couple of screen shots from the SPC Mesoanalysis page show why the storms were so strong. Take a look at the Significant Tornado (8) and Craven (130)parameters! YIKES!

Terry L. Schenk[attachmentid=77][attachmentid=78]

 

[Sam Shamburger]

Although this is my personal opinion, and is based on a quick analysis of rather poor quality radar snippets that have lots of range folding and dealiasing errors, it appears the Marmaduke/Caruthersville/Newburn supercell produced multiple tornadoes and not one long-track tri-state tornado.

Based on loops of SRV data, it appears the mesocyclone/tornado that went through Marmaduke occluded as it approached the Missouri border, and a new meso formed SE of Leonard, AR. This new mesocylone tracked just south of Kennett, MO, continued through Caruthersville, MO, then occluded and curved into southern Lake County, TN and dissipated. A new mesocyclone formed along I-155 & the Mississippi River and tracked eastward across northern Dyer County, TN, through Newbern, and into northwestern Gibson County. Then this mesocyclone occluded, and a new meso formed approximately SW of Rutherford, TN, and tracked eastward through Bradford.

Again, my quick analysis could easily be incorrect, since I've just glanced over the poor quality radar data I have from the event. However, with even hints of mesocyclone occlusions, it looks like this was not one super long-track tri-state tornado. It will take closer analysis of radar data, extensive aerial surveys, and gathering of eyewitness and stormchaser accounts to determine the true number of tornadoes with this supercell. Regardless of the number of tornadoes that are finally determined, this was a historical supercell in my book.

 

[George Tincher]

Guys, watching the same video you have watched and looking at some of the same photos you have seen, I have to agree with what most of you are saying that there is AT LEAST some minimal F4 level damage visible.

Now, how does this work when they have to bring in the expert team? If the NWS cannot assign any rating above an F3, then wouldn't it make sense for them to assign a preliminary rating of F3 (that's all these current ratings are...preliminary), then call the expert team and tell them to come have a look see?

This kind of seems to me what the NWS survey teams are indicating. They are saying "we know it's at least F3", but hinting it could be stronger. They may just keep the "preliminary" rating in place and turn it over to the team of experts to make the final call. As such, I expect to see at least one (and possibly more) of the tornadoes bumped up to F4. Could one of them be an F5? I suppose that's possible. But I haven't personally seen any photographic or video evidence to back that up, so I can't say. I did see a few homes that appeared to be swept away, but unless I am physically there and seeing how well constructed and anchored those structures are, then there is just no way to be sure.

Either way, regardless of whether these are upper end F3, F4 or F5, several of yesterday evening's tornadoes were absolute beasts that resulted in heavy loss of life and immense damage. As such, they were all very significant and will be remembered as such by those who lived through them, those who lost family and friends or those who witnessed them.

 

[Jeff Snyder]

MEG has put up lots of damage pictures from the tornadoes in their CWA. You can check them out at http://www.srh.noaa.gov/meg/events/April2006/index.htm

From those pics, I haven't really seen anything that I'd call definitive F5 damage. There are some houses that are completely destroyed, but, in almost all of those cases, the debris is laying nearby. Some of the pictures (such as http://www.srh.noaa.gov/meg/events/April20...eb/P4030031.jpg ) look a lot like the damage from the Manchester SD tornado. In addition, a few pictures below that image on the MEG page remind me of the Spencer SD F4. Of course, we don't know if the worst possible damage is contained in those pics. Some of the pics look impressive, in terms of the amount of debris, but then you can see what looks like mobile homes in the background with only a roof or outer walls missing (F2-F3).

 

[Glen Romine]

I thought the same things as Jeff. I don't see any evidence beyond F3 in the images posted to the site so far. You might think the most impressive damage images they found would be on the site - but maybe there is more that they haven't had time to upload yet. Certainly a lot of destruction - but nothing that appears to clearly be in the devastating category.

In the pic above that Jeff mentioned - I noted the trees are pushed over - but even small branches still intact. This makes me think the home may have slid off a poor foundation attachment. The debris pieces are large and in close quarters with each other.

Glen

 

[Eric Treece]

If you haven't gone back to the kfvs12.com website in the last day or so, they have added another amateur video of the Caruthersville tornado and some footage from a high school monitoring camera.