2013-05-31 EVENT: KS, OK, MO, IL

[John Farley]

Public information statement just issued:

http://kamala.cod.edu/ok/latest.nous44.KOUN.html

 

[Michael Nicolaou]

Still awaiting the full report but at what point does the definition of "tornado" need to be updated? We've known about multi-vortex systems for years, yet classified them in the singular nature. The SPC itself defines a tornado:

What is a tornado? According to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud." Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven't found it so simple in practice, however, to classify and define tornadoes. For example, the difference is unclear between an strong mesocyclone (parent thunderstorm circulation) on the ground, and a large, weak tornado. There is also disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes. It is well-known that a tornado may not have a visible funnel. Also, at what wind speed of the cloud-to-ground vortex does a tornado begin? How close must two or more different tornadic circulations become to qualify as a one multiple-vortex tornado, instead of separate tornadoes? There are no firm answers.

From the public viewpoint it is all a tornado, but from a scientific standpoint I doubt you'll ever see a "tornado" greater than 1.5 miles wide without a parent circulation and multiple vortices rotating within it. I'm interested now less in the genesis of a tornado but more in the differentiation between these two very different types of systems.

 

[Mike Johnston]

One other thing - for 2 radar scans, the storm tops were over 60,000 feet. You just don't see that very often.

 

[Bob Schafer]

One other thing - for 2 radar scans, the storm tops were over 60,000 feet. You just don't see that very often.

I agree, but also want to say that I wasn't chasing on 5-4-07, but I was nowcasting. I'm pretty sure the echo tops at Greensburg were around 72k feet. Someone else feel free to confirm or deny.

5-22-11 I also was not chasing (didn't want to go into MO), but was enroute from Emporia KS to OK in anticipation of 5-23 and 5-24. As I glanced over my left shoulder from just W of Wichita I saw the most unbelievable sight: A storm with a "dunce-cap" or "traffic-cone" overshooting top. My eyes popped out of their sockets, cartoon-style. The overshooting top, by itself, appeared nearly as large as the rest of the storm. Of course, that was the Joplin storm. I now imagine that that's what the Greensburg storm must have looked like from a distance had it not been well after sunset.

 

[Stan Rose]

Still awaiting the full report but at what point does the definition of "tornado" need to be updated? We've known about multi-vortex systems for years, yet classified them in the singular nature. The SPC itself defines a tornado:

What is a tornado? According to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud." Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven't found it so simple in practice, however, to classify and define tornadoes. For example, the difference is unclear between an strong mesocyclone (parent thunderstorm circulation) on the ground, and a large, weak tornado. There is also disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes. It is well-known that a tornado may not have a visible funnel. Also, at what wind speed of the cloud-to-ground vortex does a tornado begin? How close must two or more different tornadic circulations become to qualify as a one multiple-vortex tornado, instead of separate tornadoes? There are no firm answers.

From the public viewpoint it is all a tornado, but from a scientific standpoint I doubt you'll ever see a "tornado" greater than 1.5 miles wide without a parent circulation and multiple vortices rotating within it. I'm interested now less in the genesis of a tornado but more in the differentiation between these two very different types of systems.

Yep, that's why id like to know the details of the width. It's pretty clear there wasn't 2.6 miles of continuous EF-5 damage, that was from one of the suction vortices or satellites of the main circulation, which may very well have been EF-0 if it could be called a tornado in the first place.

 

[Michael Nicolaou]

Here's the best video evidence of the broad parent circulation with multiple vortices embedded that I have seen for this particular storm. Having the vortices "generate" at least 1/2 mile apart from each other in less than 20sec is amazing.

http://www.youtube.com/watch?v=atjCqDEJWVE&ytsession=5JVqomdoqkd7UTnqZ5FjnZMegAFuCv7l2SqoouX33Foj-zE1hoIgX2SyjwTL0cguSZ7zvv2Jihd587InFp15okwWg5OFO2QCIY0mVH4hJu2MOWK4_kApx6AcJr0oPTT2VDVlg5wOjkAVg801NtdEh3BrkeBN74RT4oI59-qSTG90psnbnOuRQnNAqD9d7Mlwh8h1WEDX2lZzfEnnMHXHKgj521_P2ptwg9vYxTfc2M0z9qoXB99B_GKXcs3RuYSYHcPWhbPZqeAhzZBHO1r5xVd8OyL5LIm7BQf7YlcIkTxg6mbWgeNHQzcs8Fc7wR02sV8KdhoUrs3TAJWAjmf9oRDQfyZyhzQjU2SjsT0X8qXVMDyqlQnUbEM-UB0m2VjijALmDGUGyTu3k5NyBsCIPIYiQ3qSzUrRD_xCJIzcesWiO9405XkRpmqDDCpJMxPCpoJam8jhB8r-OR3rAnCM7jp5cB4nrANHStXtnOHLbx69P7sMz5JIMlOpImqtcO_4IP4fIsR9tDXma0F_Vxfq2vGoae95XdSF5iIxPtFhFPCsFeT1dEbO2XEaXE-BVy0mf-v-_4wr-pMR5MDPsKpXQ4beP6NNbE2Fsm1xaN3Qkwag0xlIs_MNQH6-Zobwq5RbaTmkOKfZXrr9ZnH6t3Ee7a5ORUn7ZHRNwPRxmH-6-boL7QGvDYHvDdVc-fBRzk9p

This was not really a case of a tornado "turning"as many chasers have stated in as much as the whole broad area of circulation producing damaging vortices.

 

[Jake Orosi]

But is it a very likely possibility that an EF0 can have an EF5 satellite? I mean, which was really which's satellite in that case? I find it difficult to conceptualize an EF0 having the potential energy to pull an EF5 suction vortex.

 

[Michael Nicolaou]

But is it a very likely possibility that an EF0 can have an EF5 satellite? I mean, which was really which's satellite in that case? I find it difficult to conceptualize an EF0 having the potential energy to pull an EF5 suction vortex.

I wouldn't think of it as a satellite in this case but a vortex within the broad circulation. If you visualize it like the old Spirograph drawings you might be able to see it.

https://sites.google.com/site/geometricarts/spirograph4.GIF

The overall aspect of the circulation (the whole of the yellow feature) may have EFO damage. Within that feature the vortices will rotate around the parent circulation at potentially a much higher rate of wind speed (the individual lines within the boundary) giving you two very different types of damage based on what location was impacted by a vortice or just the broad circulation.

 

[Shawn Schuman]

I agree, but also want to say that I wasn't chasing on 5-4-07, but I was nowcasting. I'm pretty sure the echo tops at Greensburg were around 72k feet. Someone else feel free to confirm or deny.

Just took a peek in GR and the highest I could find was ~59kft.

 

[Gary Stofer]

Watching that thing forming and dissipating rapidly reminds me of Fujita's laboratory tornado.

 

[Jason McKittrick]

Supposedly it grew from approximately 1 mile wide to 2.6 miles wide in 30 seconds. I think it's really becoming clear why so many of us safety-oriented chasers were caught off guard and forced to run for our lives. Simply extraordinary circumstances.

I clearly observed this at the time but I estimated the growth to be from 100yards to 3/4 mile in 30 seconds. It is and has been my suspicion, this was responsible for the Twistex tragedy. They were very experience and knowledgable but I don't think they or anyone else anticipated that type of evolution.

 

[Karen Politte]

Still awaiting the full report but at what point does the definition of "tornado" need to be updated? We've known about multi-vortex systems for years, yet classified them in the singular nature. The SPC itself defines a tornado:

What is a tornado? According to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud." Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven't found it so simple in practice, however, to classify and define tornadoes. For example, the difference is unclear between an strong mesocyclone (parent thunderstorm circulation) on the ground, and a large, weak tornado. There is also disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes. It is well-known that a tornado may not have a visible funnel. Also, at what wind speed of the cloud-to-ground vortex does a tornado begin? How close must two or more different tornadic circulations become to qualify as a one multiple-vortex tornado, instead of separate tornadoes? There are no firm answers.

From the public viewpoint it is all a tornado, but from a scientific standpoint I doubt you'll ever see a "tornado" greater than 1.5 miles wide without a parent circulation and multiple vortices rotating within it. I'm interested now less in the genesis of a tornado but more in the differentiation between these two very different types of systems.

Well, IMHO you can't start to split hairs. Do you count every separate suction vortex/multiple vortex as singular tornadoes? No. I would say, logically, that if it is a continuous mesocyclone with continuous damage-causing tornadic contact with the ground, then it is, by definition, one tornado, from beginning to end. One multi-vortex tornado.

Some of the video I have seen shows it in its wedge-state, and you can clearly see the large, black condensation funnel with writhing vortices inside it - be they horizontal, vertical or otherwise. Still one tornado. I'd venture that - until a meso cycles off into the core and punches out the backside sans-tornado, it is ONE tornado.

KP

 

[Timothy Schaffer]

I just posted this in another thread, but thought it should be posted here as well. Brad Nelson posted what I think is the best video of how rapidly the tornado expanded. At the :53 mark, he has repositioned to an excellent vantage point south of the storm as the tornado makes its turn. At the 2:51 mark, the circulation fills the screen. Just incredibly fast expansion which I think is the primary reason that so many experienced chasers got caught in it. The forward speed seems to increase as well
http://youtu.be/AFVzauLzK_Q

Reed

 

[Bob Schafer]

Thanks, Shawn. I didn't have GR until 2008, so I was using data from CoD. It could well be that their data was corrupt somehow. Or it could be that my memory is playing tricks on me. I am old, heehee.

**sorry for dragging us OT**

Just took a peek in GR and the highest I could find was ~59kft.

 

[Brad Nelson]

I just posted this in another thread, but thought it should be posted here as well. Brad Nelson posted what I think is the best video of how rapidly the tornado expanded. At the :53 mark, he has repositioned to an excellent vantage point south of the storm as the tornado makes its turn. At the 2:51 mark, the circulation fills the screen. Just incredibly fast expansion which I think is the primary reason that so many experienced chasers got caught in it. The forward speed seems to increase as well
http://youtu.be/AFVzauLzK_Q

Reed

You're right, Reed, that is when the rapid expansion appeared to be taking place, coinciding with the sharp northward turn. One moment I had the whole tornado in the frame, I walk away from the camera for 30 seconds, and I come back to see that the tornado has exceeded the entire frame by a large margin. I've never seen a tornado expand that fast.