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

[Jeff Duda]

Skip, that video is top-notch! I can tell you poured over video and data for hours to produce this, and the results speak for themselves. Well done. I think with some condensing (for time purposes) this video could become an excellent educational video for use in spotter training or just general storm chasing training. You should consider contacting some WFOs about it and see if any would like to use it.

 

[Daniel Rodriguez]

Excellent video skip, I started it up intending to breeze through it really quick and cache it for a later but found that I couldn't turn it off and went the whole way through. Well done.

 

[StephenHenry]

Skip, thanks for putting so much time into these analyses. Incredibly valuable. Now that you've spoiled me, I'm going to make a request for version 3.

Is there enough data fidelity (temporal and spatial) to support tracking/interpolating individual subvortices within the larger grey tornado track? These could appear as darker grey regions to indicate higher wind speeds. Alternatively, recoloring the grey track with a gradient to represent absolute wind speeds would also be really interesting. Seeing this tornado sub-structure animated on the map you've already developed would be mind blowing.

 

[Skip Talbot]

That data exists from the mobile radars, so it's certainly possible. Somebody just has to sit down, piece it together, and format it. That data isn't available to the public though, at least not yet, while the researchers work with it.

 

[David Biggar]

Skip, great video! Thanks for taking the time to put it together. Similar to Daniel, I intended to watch it in pieces, but found myself glued to the screen.

 

[Mike Szentes]

Sorry David for the late response! Happy New Year. I'll update my profile here with full name, etc. Mike Szentes. Below Vimeo link, the opening still, has where we were by time and bearing.
http://vimeo.com/channels/stormchase/67849759.

Stills and other videos are here.
http://picasaweb.google.com/szentesm

I've already submitted links to http://el-reno-survey.net.

 

[Dan Robinson]

In response to a frequently asked question of why I chose my positioning and route of travel on May 31, 2013, tonight I put together this map which explains it. Perhaps this will clear up some of the confusion. Click on either the link or the thumbnail to view the full size image.



Full size:

http://stormhighway.com/may312013/elrenotrack2025.jpg

In the time that has since passed, I've realized that one of the big mistakes I made was missing an ominous warning sign: the very (unusually) wide rain-free gap between the tornado and the forward flank precip core to the north. The storm's forward flank core never deviated from its eastward track. This is what I've come to call a "yo-yo" effect, where the tornado/hook stretches far to the south, then snaps back north. If the storm had been tracking southeast like I had expected, then the forward flank precip should have also moved farther south and started to overtake me. It never did, I was in clear precip-free air the entire time west of 81.

I hope this is helpful and I would like to hear comments and questions.

EDIT: I discovered while watching Tim Marshall's 2014 Chasercon presentation that he already coined the 'yo-yo effect' term to describe an extended hook that snaps back to the north.

 

[Danny Neal]

That's a very interesting observation about the forward flank Dan. Thanks for sharing again.

 

[Adam Lucio]

That actually makes a lot of sense, Dan. I believe the Bowdle storm did this same thing. Definitely something to watch for on future chases.

 

[Nick Nolte]

The yo-yo description reminds me of the 5/20/13 Moore tornado. I remember thinking the appendage was way the hell away from the ff, and the radar animation shows it kind of pulling itself closer as it neared where I-44 turns north towards OKC which corresponds to the temporary northward jog in the survey path, not as dramatic as El Reno's turn. I wasn't on Moore and I'm not sure from the videos if there was any wide rain-free gap that correlates as Dan describes, but that was the first thing that came to mind when I read that description.

 

[Marcus Diaz]

Nick I know exactly what you mean. I screen grabbed the radar when I noticed that in the storm.

At first I didn't think there was any way that that was the updraft base. But the more the storm matured, the more I realized there was some wicked speration of updraft and FFD. You could almost visualize the rain free base, tornado, and RFD from just looking at the radar.

 

[JamesCaruso]

In response to a frequently asked question of why I chose my positioning and route of travel on May 31, 2013, tonight I put together this map which explains it. Perhaps this will clear up some of the confusion. Click on either the link or the thumbnail to view the full size image.



http://stormhighway.com/may312013/elrenotrack2015.jpg

In the time that has since passed, I've realized that one of the big mistakes I made was missing an ominous warning sign: the very (unusually) wide rain-free gap between the tornado and the forward flank precip core to the north. The storm's forward flank core never deviated from its eastward track. This is what I've come to call a "yo-yo" effect, where the tornado/hook stretches far to the south, then snaps back north. If the storm had been tracking southeast like I had expected, then the forward flank precip should have also moved farther south and started to overtake me. It never did, I was in clear precip-free air the entire time west of 81.

I hope this is helpful and I would like to hear comments and questions.

Dan, thanks for putting this together and for continuing to share insights from this event over a year and a half later (which I was not on, by the way, flew home that morning, which I will probably always regret.... )

I have two questions:

1. Since the objective of your post is to explain your route and positioning, I wanted to ask a clarifying question raised by your map. You have the right third marked "tornado clearly visible." This includes the area where the tornado was moving northeastward, it is south of you, yet you still continued east. During this time, did you realize it was going to cross your path and you were trying to beat it, or did you still not realize the tornado's motion at that point?

2. The "yo-yo" effect is very interesting. This is my first time hearing this concept. Have you (or anyone) seen this written about previously and is it a recognized aspect of storm evolution, or is it an observational anecdote at this point? If it is the latter, it would be interesting to pursue. On a related note, you say that you should have paid more attention to the FFD movement. I always thought it was NOT a good idea to focus on FFD movement, because there can be expansion/contraction of the precip that is not correlated with storm motion and can be misleading? Or I guess maybe the answer is that you wouldn't read too much into it if it was moving southeastward because it could just be expansion of the precip as opposed to storm movement, but the fact that the FFD was NOT moving southeast is enough to tell you that the storm could not be moving southeast?

Thanks in advance for your insights!

Jim


Sent from my iPad using Tapatalk HD

 

[Dan Robinson]

During this time, did you realize it was going to cross your path and you were trying to beat it, or did you still not realize the tornado's motion at that point?

James, when the tornado began making its turn, it was obscured from view by the rain. From my vantage point, I did not realize what was happening until well after crossing Highway 81. I was already at least 3/4 mile east of 81, eastbound on Reuter, when I recognized what was happening. At that point, I could see that the rain curtains were moving at tornadic speeds and were actually inside of/part of the tornado, not just the 'benign' outside rain wrap. There was no time to turn around and head back to 81 to go north. Turning north on Alfadale or Radio (my next north options) would have just kept me in its path (not to mention necessitating slowing down to take a 90 degree turn), so the only real option I saw was to go east. In retrospect, I could have turned around and escaped westward, but at the time I don't think I would have taken the chance of stopping and doing a k-turn with that bearing down on me.

2. The "yo-yo" effect is very interesting. This is my first time hearing this concept. Have you (or anyone) seen this written about previously and is it a recognized aspect of storm evolution, or is it an observational anecdote at this point? If it is the latter, it would be interesting to pursue. On a related note, you say that you should have paid more attention to the FFD movement. I always thought it was NOT a good idea to focus on FFD movement, because there can be expansion/contraction of the precip that is not correlated with storm motion and can be misleading? Or I guess maybe the answer is that you wouldn't read too much into it if it was moving southeastward because it could just be expansion of the precip as opposed to storm movement, but the fact that the FFD was NOT moving southeast is enough to tell you that the storm could not be moving southeast?

When the tornado was at its southernmost point, there seemed to be an abnormally wide separation from the hook/meso and the FF precip. There's always some type of gap there (part of the vault region) but in this case, it seemed exceptionally wide.

 

[Dan Robinson]

A previously unpublished video from El Reno has been posted by Allan Gwyn. It appears to be shot from a perspective close to mine and the Samaras/Young vehicle at first near the airport, culminating with being overtaken by the tornado after turning south on Highway 81.

 

[Paul Knightley]

At just over 4 mins in, you can see us heading east past the videographer, and then he is just behind us at an intersection (we're in a GMC SUV). It then looks like they were behind us, in a small convey until US81 - at this point I made the call for us to continue east, remarking 'I don't know why you'd go south'...I have always wondered what it would have been like...I'm glad we didn't!