Tornadoes with Tentacle Like External Vortices!!

Discussion in 'Advanced weather & chasing' started by Bill Tabor, Apr 30, 2011.

  1. Bill Tabor

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    Ok, we've all seen the dramatic Tuscaloosa tornado with it's squid like external 'tentacle' vortices. That tornado IMO looks incredible as tornadoes goes and likely ranks amongst the very top, but what are those freaking War of the Worlds like tentacles? I don't remember seeing tornadoes sporting those in the past. The first time I saw them was last year on my Goodnight Tornado. I loved them then, but the Tuscaloosa torn has them all over and they seem to be fairly long lived and generated regularly? What are these things? Can anybody explain them? How many of you have seen or chased tornadoes with them? Show your pics! Seriously this seems like some cool stuff. Perhaps they are a sign of a very violent tornado or perhaps a type of multi-vortex with one main parent circulation? However, unlike satellite tornadoes these typically are not on the ground. Makes me now wonder again about the Ft Leonardwood tornado pic and it's odd vortex crossing it. If anyone knows the science of these things...let's here it please. Here's a pic of my Goodnight torn (it had many faces and looks during the 20 minutes it was down).
     
  2. Dan Robinson

    Dan Robinson WxLibrary Editor
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    I'm wondering if this is somewhat of a "smoke ring" effect, with rapid upward motion causing 'rolls' to form around the perimiter. A smoke ring forms with a rapid 'puff' of vertical air through stagnant or slow-moving air, with this tornado it's as if the 'puff' was a steady stream of high-velocity air interacting with slower-moving air along a sharp boundary.
     
  3. rob.cannon

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    I did some Googling and I found that many of large violent wedges in the past have been reported to display these types of features. I saw a few of them on June 17th in Southern Minnesota, but nothing as prevalent as on the Tuscaloosa tor. Upon further searching the only explanation is they are just suction vortices. Thats all I have.
     
  4. DRMabe

    DRMabe EF1

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    It was pretty wild watching them wrap around that thing. Took some still captures from my vid of them.
     
  5. This was brought up in the DISC. thread.
     
  6. rob.cannon

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    watching it live form the tower cam was incredible! I was thinking "an already violent tor is about to spawn a good sized satellite... this day is about to go from bad to really bad!"
     
  7. Bill Tabor

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    Unable to insert a picture last night, or this morning of my Goodnight tornado with external vortices due to ST performance issues and lockups. Here is the link to it as an example in a addition to Tuscaloosa:

    http://www.tornadoxtreme.com/20100422_163313.jpg
     
  8. Bill Tabor

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    Anybody have any other examples of this to post. I'm almost wondering if this is some type of new phenomenon. I know that doesn't make sense in regards to atmospheric physics but how come only recently torns have it, or am I mistaken. What about those wedges mentioned. Provide a link...what year and what tornado? Are these extremely rare?
     
  9. Scott Weberpal

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    We're seeing them more and more now because there is more and more up-close and high quality video being taken of strong tornadoes.

    Going back only 10 years...would there have been much, if any video of the tornado in Tuscaloosa compared to what was taken a few days ago?

    Mulvane '04

    http://www.mesoscale.ws/pic2004/040612-13.jpg - look at the upper half of the tornado.
    http://www.mesoscale.ws/pic2004/040612-14.jpg - zoomed in with "tentacles" everywhere.

    Red Rock '91 had a substantial horizontal vortex, and I believe that if Prentice/Rhoden would have been closer, you would have seen "tentacle" whipping everywhere around the tornado.

    There is nothing to indicate that only recent tornadoes have these "tentacle", except much more fantastic video. Some tornadoes have them and some dont', and with better and more video, we'll see more and more of the tornadoes that do.
     
  10. Jeff Duda

    Jeff Duda Resident meteorological expert
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    This is nothing new. I can remember seeing such auxiliary vortices on tornadoes from videos I watched when I was a kid of tornadoes in the 70s, 80s, and 90s. Haven't you seen Bobby Prentice's video of the Red Rock F4/5 tornado crossing I-35 on 26 April 1991? http://www.youtube.com/watch?v=5zUJJH_MSZI
     
  11. Bill Tabor

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    Scott / Jeff, yep, I see the Mulvane torn does appear to have some smaller ones up top half although mostly minor. Red Rock I had never seen. Pretty cool and it does have one decent horizontal vortex which dissipates. My Goodnight torn had these much wider around the tube and larger vortices compared to Mulvane (not just in that picture). Tuscaloosa though appears to be an extreme example with these things being consistently hanging off multiple sides at the same time. I was thinking about it and that tornado kind of reminds me of the old War of the Worlds movie where the guy is holed up in the farmhouse and one of those aliens comes running through the room with his tentacles swinging / dangling. :D

    Still seems this is a rare phenomenon - unless we have more and better examples. I wonder if it is any indication of strength, etc.
     
  12. Chad Ringley

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    The Mulvane tornado developed those vortices in conjunction with a substantial kink in the main circulation up top. I remember thinking when seeing it that it had something to do with that kink. Wildest thing I've ever seen.
     
    #12 Chad Ringley, Apr 30, 2011
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  13. Kevin Walters

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    I talked to a farmer back in the mid 80's who witnessed the Charles City, Iowa tornado in 1968. His farm was in Southern Floyd county about 20 miles SW of Charles City. The tornado missed his farm by one mile to the North. He described it as having "spider legs" moving out away from the tornado itself. Sounds similar to what happened with some of the tornadoes this week.
     
  14. Joshua Nall

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    Sorry if this has been posted already but I've not seen it linked yet, could have missed it. It has over 3 million views so it's a popular one.

    http://www.youtube.com/watch?v=5ohIVzIZLuQ&feature=player_embedded

    The video is shaky, sounds like a woman, who is very shakin' herself being so close to this violent tornado. But the middle part of the video ranks up there with the most violent video I've ever seen.

    As for all the external vortices. I'll put it into terms that I understand. Seems to me the air accelerating in so incredibly fast at ground level, and then spiraling up into the tornado causes the horizontal rolls... just like at the back side edge of a paddle through water. Seems logical to me the most violent tornadoes would have these... cause the rolls get tight enough, intense enough to become visible with condensation. What I'm describing is probably the same thing as the smoke ring effect Dan mentioned. I think the Mulvane vortices are something a little different in that they are not associated with the mostly horizontal wind speed along the ground. Just me thinking out loud.
     
  15. Bill Tabor

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    That may be that 'dead man walking' phenomenon. Similar but multi-vortex on the ground rather than tentacles dangling in the air. Dead man walking is legendary bad ass too - per Indian folklore.
     
  16. Bill Tabor

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    Yeah, I think you guys may be on to something there. Plus during the 'Tuscaloosa' outbreak day I remember watching mesoanalysis loop of 850-250mb Diff. Divergence which tracked right along with the violent outbreak cells. Seems like a large scale wave of lift was just sucking air from below. Perhaps those vortices are evidence of such large scale massive lift.
     
  17. Neal Wikner

    Neal Wikner Lurker

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    At the Minnesota Storm Chasing convention this year Kinney Adams of Tempest Tours had a presentation on the Keister, MN tornado of June 17, 2010. His presentation was all about the vorticity and his video had a great examples of this phonomenon as well. He called them 'vorticity noodles'. Don't recall any explanation of their creation though.
     
  18. Greg Blumberg

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    The theory that I heard recently is that it's a combination of the multi-vortex nature of the tornado and the strong wind speeds literally tilting the sub-vortices into a horizontal direction. Thus I guess that it's a good sign of the violent nature of the tornado.

    The problem with the tornado (from the theories) is that it's not formed by tilting of vortex lines into the vertical from the horizontal, but rather the vortex is being built by stretching and other different processes. If you tilt vorticity, you don't generate a circulation at the ground.
     
    #18 Greg Blumberg, May 1, 2011
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  19. Dave Kaplow

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    The Cullman Tornado had even more impressive horizontal fingers than Tuscaloosa, starting at around the 4:45 mark on this tower cam video. They seem to be found on many of the violent tornados from the 27th. At a guess, I'd say you need strong vertical motion to generate them. The actual physics behind these things is probably pretty chaotic.
     
  20. J Tyler

    J Tyler EF3

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    Last fall, my wife and I followed a HUGE wall cloud in Texas that had multiple (5-6) thin to moderate funnels that kept spinning up out the SIDES of the wall cloud, reaching outward. It was very dramatic to see. The wall cloud only produced two quick tornadoes that reached the ground, both of which were small and short lived. The whole thing looked more like "Medusa" moving across the sky. Of course, I didn't have the video camera rolling during the most obvious part of the event, but here is the wall cloud I'm talking about:

    Watch video >

    Totally off subject, but the discussion in the video was because we had placed ourselves between two areas of rotation (one in front of us, the big wall cloud, and a newly forming wall cloud to our 3 o clock), and we were trying to keep position on both of them, but hail was coming...
     
    #20 J Tyler, May 2, 2011
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  21. My guess after watching several videos would be a combination of the violent upward motion creating some sort of horizontal rolls, and stretching of horizontal vorticity by the intense inflow of air getting sucked violently into the vortex. Generally, I believe tornadoes are thought to pull most of the air into the vortex near the surface, but maybe with some of the more violent examples, the pressure falls and violent upward motion become strong enough to the point where the vortex begins pulling more air in from the sides. Imagine hooking a vacuum up to some sort of brittle tube, and then impeding the flow of air into the base of the tube... the vacuum would likely break a hole in the side of the tube in an attempt to fill the void created by the vacuum. So maybe the pressure falls are so great in some of these examples that the vortex needs to pull more air in horizontally at different levels to attempt to equalize the pressure inside the vortex to that of the pressure outside the vortex. But as for the Cullman tornado, I have never seen anything like that. That is absolutely stunning!
     
  22. Jeff Duda

    Jeff Duda Resident meteorological expert
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    This kind of behavior is probably due to a phenomenon called vortex breakdown. There are a number of articles in the fluid dynamics world on this phenomenon. One such article in the Bulletin of the AMS is here.
     
  23. Skip Talbot

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    I saw some of this going on with the Albert Lea, MN EF4 from June 17, 2010 as others have already mentioned in the thread. My take on the winds that might have been at play during the time with the RFD and inflow's vertical interactions creating strong horizontal vorticity:

    [​IMG]

    Jesse Risley has a nice zoomed shot of the tornado a few minutes earlier and you can see tentacles within the main circulation.

    These tentacles definitely need a subset of ingredients that not all tornadoes possess. I don't recall seeing any with the Bowdle, EF4. I'm guessing the inflow needs to be near saturation and there need to be a lot of small scale areas of rapidly rising and rapidly descending winds in close proximity as opposed to one dominant updraft and one dominant RFD.
     
  24. DRMabe

    DRMabe EF1

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    A still from my video of the Tuscaloosa Tornado showing the Horizontal Vorticity
    [​IMG]
     
  25. Robert Edmonds

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    I should go back to my simulations from earlier this year http://bit.ly/jjx9d9. Most of these tentacle vorticies wrap counter-clockwise with height around the main vortex. If you consider just a line vortex of this nature (wrapping in this manner), it should produce vertical velocity upwards. This would carry the line vorticity upwards (as it appears most of them do), with no stretching needed (assuming cyclonic rotation). If it was to wrap clockwise with height and still be cyclonic, the vertical velocity would be downward, and would carry the vortex lines downward too (but I don't see many with these attributes).
     
    #25 Robert Edmonds, May 2, 2011
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