The El Reno, OK, Tornado of May 31, 2013: A Case Study

In-depth discussion of the infamous El Reno, OK, tornado of May 31, 2013. We'll discuss the meteorology behind the event before diving into the behavior and mechanics of the tornado, including the tornadogenesis process, satellite and sub-vortices and how they impacted storm research teams, the tornado's erratic/deviant motion and how it could have been forecast, and more.
Thanks to Brett Wright for the awesome thumbnail photo, and to Micah Hart for providing the RadarScope imagery in this video.
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Chapters:
0:00 Introduction
2:51 Meteorological discussion
23:48 Event progression/radar overview
29:17 Non-descending tornadogenesis
39:23 Satellite vortex (w/ hi-res RaXPol data)
41:56 Deviant tornado motion
55:12 Multi-vortex behavior
57:16 Violent sub-vortex and its impact on TWC/Twistex crews
1:05:06 Strong anticyclonic tornado
1:07:04 Analyzing the transition to flooding threat for OKC
1:10:41 Conclusions
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Resources:
NWS Norman event page: www.weather.gov/oun/events-20...
"A Multiscale Overview of the El Reno, Oklahoma, Tornadic Supercell of 31 May 2013" - Bluestein et al. 2015: journals.ametsoc.org/view/jou...
"Tornadogenesis and Early Tornado Evolution in the El Reno, Oklahoma, Supercell on 31 May 2013" - Bluestein et al. 2019: journals.ametsoc.org/view/jou...
"The Role of Multiple-Vortex Tornado Structure in Causing Storm Researcher Fatalities" - Wurman et al. 2014: journals.ametsoc.org/view/jou...
"The Multiple-Vortex Structure of the El Reno, Oklahoma, Tornado on 31 May 2013" - Bluestein et al. 2018: journals.ametsoc.org/view/jou...
Cameron Nixon's blog article on the deviant tornado motion hodograph technique: cameronnixonphotography.wordp...
"Anticipating Deviant Tornado Motion Using a Simple Hodograph Technique" - Nixon and Allen 2021: journals.ametsoc.org/view/jou...
"Reexamining the Vertical Development of Tornadic Vortex Signatures in Supercells" - French et al. 2013: journals.ametsoc.org/view/jou...
"Photogrammetric Analysis of the 2013 El Reno Tornado Combined with Mobile X-Band Polarimetric Radar Data" - Wakimoto et al. 2015: journals.ametsoc.org/view/jou...
"Formation of Mesoscale Lines of Precipitation: Severe Squall Lines in Oklahoma during the Spring" - Bluestein and Jain 1985: journals.ametsoc.org/view/jou...
"Analysis of Tornadic Supercells Using Two Rapid-Scan, Mobile Doppler Radars" - Greenwood 2021 (my Master's thesis): shareok.org/handle/11244/330737

[@JR-pb5dz]

Probably the most underrated channel still out there regarding convective breakdowns. One of these days my hope is the subscriber numbers will skyrocket

[@ConvectiveChronicles]

I really appreciate that; thank you!

[@DaydreamNative]

This channel and Tim Vasquez' Forecast Lab both deserve way more than they currently get. Someone needs to teach the algorithm about quality over hype.

[@ConvectiveChronicles]

@@DaydreamNative Thank you! Love Tim's content; his handbooks were like the bible when I was first getting into severe wx forecasting.

[@lennys6059]

@@DaydreamNative thanks for mentioning Tim, now I have a whole other channel to deep dive and learn about storms! Looks like he does some serious breakdowns with the nitty gritty like Trey does

[@DaydreamNative]

​@@lennys6059 Yeah, it's a slightly different format with a more general focus given the day to day schedule and intends to teach how to analyse your local weather yourself rather than trying to cover it all, generally not quite as in-depth or comprehensive as what Trey puts out but equally essential viewing IMO.

[@ac7666]

College level lectures that are entertaining and free to watch, as someone with a massive intrest in Meteorology and no desire to go to a proper university, these videos have taught me so much I never thought I would be able to learn. Thanks for all your hard work Trey, it is much appreciated, I hope your channel will grow to whatever size you desire it to. c:

[@ConvectiveChronicles]

Thank you so much! I really appreciate that!

[@Zanenoth]

Alongside watching this you should also check out NWS Norman it's the actual National Weather Service and they have free seminars

[@anja0106]

Imagine living in Moore and having your house destroyed on the 20th, so you go stay with friends/family in El Reno.

[@leatherDarkhorse]

Lucky the elreno was open field

[@Asterra2]

Wow. I randomly looked up El Reno sub-vortices, not really expecting to find anything more than Skip Talbot's old videos, and somehow I picked the exact perfect day to do that search. Gonna give this a solid watch when I can.

[@ConvectiveChronicles]

Haha enjoy!

[@claybarnett6350]

The 55min-65min section is totally mind-boggling information. Thank you for breaking this down for us!

[@michaelross1452]

The cape values were in fact that high. Storm chasing that day, we saw close to 6000 cape values before(i mean within 30 mins of storm initiation) and ground obs at highway 81 just south of el reno showing a strong backing wind ahead of the frontal boundary. I have not seen since then as high of cape values with such a storm. This storm veered southeast immediately after el reno. With the meso splitting in two. Creating a semi quasi linear line. It produced tornadoes in south okc as well. Very dynamic and very rare. And remember this was a week AFTER Moore took another direct ef 5.

[@commiehunter733]

I heard Jarrel had CAPE 7500...

[@ParabolH]

This is literally the first video in years that I have put my devices down and just watched. Absolutely amazing.

[@ConvectiveChronicles]

Thank you so much!

[@zehnerdygamer3329]

If I could make a suggestion - the Tri-State Tornado is shrouded in a lot of mystery - documentation may not be as readily available on that storm, but I think it would be quite a piece to look at if you made an analysis of that!

[@EveryDooDarnDiddlyDay]

Isn't it generally believed nowadays that the Tri-State was a series of tornadoes from a cyclical supercell? Or perhaps there is just not enough evidence to make any real conclusion.

[@thiccboi1741]

i completely agree that an analysis of the tri-state tornado would be great, but without modern radar and documentation of the storm, it definitely would be a very challenging and inhibited video due to those factors

[@ConvectiveChronicles]

I agree; it's on my list! Only issue with those old events is the data archives are quite sparse, but I think the Tri-State Tornado has enough literature out there that I could construct a solid video on it.

[@ConvectiveChronicles]

Correct, it’s believed to be a tornado family rather than one long track.

[@plawson8577]

@@ConvectiveChronicles Use the 2021 Quad State Supercell as a starting off point for the Tri State Storm. Because theory suggests that the 1925 Tri State Tornado was likely identical to the 2021 Kentucky Tornado.

[@TallyTechandTroubleshooting]

Wow, Trey! This was absolutely fantastic!! I will have to watch this several times to ingest everything presented here. Thank you VERY much for putting this incredible case study together!!

[@ConvectiveChronicles]

My pleasure; thanks so much, Tal!

[@brandonwilliams6460]

Tbh I only understand about 20% of the information but these videos are so well put together and explained. For someone like me (with little to no meteorology experience) to end the video and learn something... you are talented. Thank you for the time and effort you spend on this, it's appreciated!

[@ConvectiveChronicles]

Thank you for the kind words!

[@Rhi_wx]

Trey, this is an absolutely incredible breakdown. There is so much information to digest. It'll definitely warrant another watch (or two!) What an absolute beast of a storm! My mind is blown by the anti-cyclonic multi-vortex sub vortex. I think it's amazing how there weren't even more casualties and fatalities with this storm. Wonderful stuff Trey, keep up the groundbreaking work 👏

[@ConvectiveChronicles]

Thanks so much, Rhi! Thankfully this storm wasn't 30 miles east, as that would have been a worst case scenario for OKC.

[@distantworlds9104]

Your channel is one of the best discoveries I've made on KZbin in a long time. Thank you so much for all these excellent analyses!

[@ConvectiveChronicles]

I really appreciate that; thank you!!

[@WouldYouKindlyPls]

Literally was watching footage of this last night and wondered if/when you were going to cover this. Thanks so much!

[@ConvectiveChronicles]

Thank you for watching!

[@SynthWoof]

The best breakdown of the event! In painstaking, granular detail that many other videos miss... especially the part about the motion and speed of the main inner vortex! Astonishing!

[@ConvectiveChronicles]

Thank you so much!

[@sampb0906]

As always I love the videos. I’ve been storm spotting for 2 years now and this year I’ve been diving deep into the meteorology and you have been a big part in that so thank you!!!

[@ConvectiveChronicles]

Really happy to hear that! Thank you!

[@DeniseS328]

I really appreciate your lectures/case studies on these tornados, they are invaluable for those of us who never stop learning. Thank you!🙏

[@ConvectiveChronicles]

Thank you so much!

[@deransadventures]

Man, great work as always. Thanks so much for doing these.

[@ConvectiveChronicles]

My pleasure; thank you!

[@crazycatlady5629]

Wow 🤯 Amazing job! Thanks for making this! This video was worth waiting for.

[@ConvectiveChronicles]

Thanks so much!

[@windwatcher11]

So comprehensive! Amazing work! I'll be reading those journal articles. You do a great job with these analyses! Thank you so much for your effort.

[@ConvectiveChronicles]

Thank you so much!

[@StayPrimal]

Most legendary tornado probably. Thank you for covering this, gonna be great !

[@ConvectiveChronicles]

Thank you!

[@marsupialsrock010]

Captain Clutch with the timing, I needed the distraction! Thank you!

[@SylvieJ47]

Fantastic. Best case study yet. Love the depth and explanations.

[@ConvectiveChronicles]

Thank you!

[@shadowscollide44]

Thank you for another amazing video! I've learned more from you than anyone else!

[@ConvectiveChronicles]

Thanks so much!

[@jonathanbiemans9721]

Awesome work! Love looking at these, there such a great tool to understand more severe weather concepts as I move towards my atmospheric science degree. Keep up the great work!

[@ConvectiveChronicles]

Thank you!!

[@brad5349]

This is the best data coverage on the deadly sub vortex, I had no idea it was moving at those speeds, incredible.

[@vexossoul]

Absolutely beautiful work, please continue to make content like this!

[@ConvectiveChronicles]

Thank you!

[@winchestermodel7044]

This is a true masterpiece. Amazing in depth analysis of so many different facets of this incredible storm. Subscribing!

[@LoriGraceAz]

Absolutely incredible breakdown. I learned a ton and appreciated this. Thanks, Trey!

[@ConvectiveChronicles]

Thanks so much, Lori!

[@michaelonesty]

Thanks for another awesome video Trey!!

[@ConvectiveChronicles]

You bet, thanks for watching!

[@dakotastrawn93]

Amazing work man. If you get the time, I would love to see your breakdown of the early May 2003 tornado outbreak. My hometown of Jackson, TN was struck by the 2nd of 3 (E)F4 tornadoes in just 9 years on May 4, 2003. I feel like that was a really interesting setup given the widespread and long lived nature of it. Keep up the great work!

[@ConvectiveChronicles]

Thanks so much! I will definitely add it to the list!

[@reedschaffer4086]

Just great stuff Trey. Thanks so much. Interestingly, the Moore tornado, eleven days earlier, did a bit of a "failed occlusion" loop as well.

[@ConvectiveChronicles]

Thank you! You're right; these failed occlusion cases are very interesting!

[@mavtaku5405]

Love the long form content! I've watched plenty of tornado and storm related channels but you are by far my favorite. I live in central Oklahoma not but 20-30 miles from this tornado at the time. It was wild trying to find shelter as this monster was coming through

[@ConvectiveChronicles]

Thanks so much for the kind words! Can’t imagine what that day must’ve been like living so close to that storm; I live in Norman now and haven’t yet had a scare like that. I’m sure it’s only a matter of time.

[@dragnflei]

This was fascinating. I’m glad you spent some time going over the behavior of the tornado. Seeing that info on the sub-vortices was kind of mind-blowing. And I’d not heard that the anti-cyclonic tornado was multi-vortex, too. Thanks again, I was really excited to see you’d done this case study.

[@ConvectiveChronicles]

Thanks so much!

[@TheLocalLt]

Skip Talbot got video of the anti-cyclonic, it was like a mini version of the El Reno tornado, with a rotating cloud base producing several constantly changing vortices (mostly without visible condensation funnels)

[@BenPat88]

Amazing vid, best yet Trey!

[@ConvectiveChronicles]

Thanks so much!

[@RUNNOFT71]

I can't believe how much I learned from this. Very awesome video man!

[@ConvectiveChronicles]

Thank you so much!

[@SvrWxArchive1807]

This might be the best one yet! Great work. I will always remember this day, but not particularly because of El Reno. This day also had a QLCS tornado event in the St. Louis metro area with an EF-3 which went right through everyone I know and love. My grandmother, who nearly took a direct hit, was hard to reach for an hour. However, I was so focused on STL that I had no idea what was happening in Oklahoma. But I remember the first image I saw from that day was the destroyed TWC Tornado Hunt vehicle. Since I was an avid TWC viewer, that chilled me to my bone. Again, excellent work!

[@ConvectiveChronicles]

Thank you! This case study did require a lot more work because this tornado has so many unique/noteworthy facets, so I appreciate that! Wow, I hope your grandmother came out ok. There was definitely a volatile atmosphere in place up that way, so I'm not surprised there were some strong tornadoes.

[@SvrWxArchive1807]

@Convective Chronicles Yeah she was fine. No one was killed or injured in the tornado. The actual tornado went a quarter mile to her north, but their neighborhood caught the RFD surge with estimated 100mph winds which snapped several dozen trees in her neighborhood.

[@ConvectiveChronicles]

Wow, that’s crazy. Glad she (and everyone else) made it out ok.

[@dragnflei]

I lived in STL at that time, too, and it was really scary. I’m glad your grandmother and other loved ones were ok.

[@morganw.2473]

Thanks again for doing these!

[@beanie168]

Fantastic breakdown. So clearly articulated with so much detail.

[@ConvectiveChronicles]

Thanks so much!

[@beanie168]

@@ConvectiveChronicles You're welcome ;)

[@alexis_ianf]

Just saw this on my recommendation definetly worth watching and very informative learning about how this tornado formed, its structure and what makes it not only the widdest tornado and its unusual nature.

[@ConvectiveChronicles]

Thank you for the kind words!

[@SweetestSweden]

That sub vortices map was horrifying! Thank you for the in depth breakdown on a tornado that seemed extremely malicious and targetted!

[@Cameron_Chase13]

Well done as always Trey!

[@ConvectiveChronicles]

Thank you!!

[@dmedme9268]

This content is INCREDIBLE.. This channel is incredible, SUPER glad I came across this channel.. I’m hooked..just.. wow!

[@ConvectiveChronicles]

Thank you so much for the kind words!

[@dmedme9268]

@@ConvectiveChronicles and thank you!!!

[@hippy_johnny1773]

The El Reno tornado is one of my favorite of all time, love the video! And keep up the amazing work!

[@ConvectiveChronicles]

Thanks so much!

[@g.f.9862]

Superb work. Best analysis on the web. Much appreciated.

[@ConvectiveChronicles]

Thank you!

[@g.f.9862]

@@ConvectiveChronicles I have learned more about the true nature of the elusive subtleties of these meteorological events here than anywhere else in the last 20 years. Bravo!

[@ConvectiveChronicles]

@@g.f.9862 That really means a lot, thank you!

[@nymperico]

This is amazing, thank you! Folks in the area should visit the Big Well museum in Greensburg, KS which displays an amazing retelling of the event along with some of the debris and a tower to look out at how the town changed. I definitely cried due to how real their museum made it feel. They also include the story of how they recovered which is super inspiring.

[@ConvectiveChronicles]

Thank you! I made my first visit to the Greensburg museum last year; it was an incredible experience. I always enjoy driving through town and seeing how far they’ve come since that fateful day.

[@VivianLund]

Thanks! Thanks! I learn so much from your lectures on theses weather events.

[@ConvectiveChronicles]

Thank you so much; I really appreciate that! I hope to resume these case studies once things slow down weather-wise this summer.

[@williamsweather]

Loving the case studies! Very informative 😊

[@ConvectiveChronicles]

Happy to hear that; thank you!

[@NeonBeeCat]

amazing discussion, more information that i previously had not heard about

[@ConvectiveChronicles]

Thank you!

[@TAStormChasing]

Excellent case study. Could watch mobile radar scans of tornadoes on loop for days! Haha, thanks for upload. Also, Bennington would be an interesting case. I'm guessing that deviant track was the tornado wrapping around the entire mesocyclone? Cheers!

[@ConvectiveChronicles]

Thank you! Bennington is on my list; that one actually attained its almost stationary/slightly retrograding motion because of advection by the low-level storm relative wind...using the deviant motion hodograph technique, the deviant tornado motion vector was literally almost at the exact center of the hodograph grid (i.e. nearly stationary motion): www.ustornadoes.com/wp-content/uploads/2021/03/20130528_2300_39.32_-97.92_RAP_23Z_F00.png

[@swelch2661]

I really enjoyed to watch this, it was like half a Case Study and half a meteorology course

[@ConvectiveChronicles]

Thank you; glad you enjoyed it!

[@neekorobison1458]

Whoa the Elmer tornado was mentioned here? That was a curveball. I was working with TTU's atmospheric sciences team on that one. Cool that it was part of your thesis!

[@ConvectiveChronicles]

Yes! Enjoyed working with the RaXPol and MWR-05XP data from that case, was a really interesting tornado.

[@TheLycanStrain]

I'll post this again, I absolutely love your videos and listen to all of them either on the commute or during free time Thanks for all the effort you put into these. I'm a massive fan of Cameron Nixon so I'm very happy to see him cited here. You've made me so much smarter on weather and especially tornadoes and I thank you for that. Also the obligatory "elevated mixed later" aka EML reference

[@ConvectiveChronicles]

Thank you so much! I always try to work in Cameron's stuff when I can, as it really makes envisioning how the wind profile relates to the environment/possible hazards easy. And haha yes, the obligatory EML reference...wouldn't be a Convective Chronicles forecast discussion or case study without a reference to EML...

[@dryvoutcm]

Really impressive work. Definitely earned my sub. Thank you!

[@ConvectiveChronicles]

Thank you so much!

[@outtaroute92]

Great video here. I don't understand most of what you're discussing, but it's still always so fascinating to watch and learn a little bit and you've even sparked an interest in meteorology for me. This is something I would really enjoy to research and learn more. Do you by chance happen to have plans to do an in depth analysis of the May 20th 2013 Moore, OK EF5? I'd be very interested in seeing that one as well. I lived in Okemah, OK at this time and I remember watching both of these monsters on the news and I was just awestruck and heartbroken at the same time.

[@ConvectiveChronicles]

Thank you! So happy to hear the videos have gotten you interested in meteorology! Yes, the Moore event is high on my list.

[@outtaroute92]

@@ConvectiveChronicles that's awesome to hear, I'll definitely be looking forward to it. Thank you sir!

[@chrismack5908]

Oh goodie! Goodie! Haven't even watched yet and am excited! I'm going to take time to view and absorb! Thanks Trey!

[@ConvectiveChronicles]

Thank you; enjoy!

[@Duck_87]

Great discussion trey I love these briefings

[@ConvectiveChronicles]

Thank you!

[@aaronjones1469]

Awesome👍🙂 case study. I remember this one very well, it occurred on the day before I graduated school.

[@ConvectiveChronicles]

Thank you! Yeah, this event is hard to forget...a lot of non-weather people I know even know about it.

[@UGA2933]

As someone who is currently in an atmospheric science program your videos are awesome. Wish i could've gone to OU but UGA was home. I cant wait to chase some storms soon though.

[@ConvectiveChronicles]

Thank you! Many good storm chasing opportunities ahead!

[@ChrisJones-lw8ss]

Great work, Sir. Thank you!

[@ConvectiveChronicles]

Thanks so much!

[@tobyschmitt4325]

Awesome video Trey! I am not a meteorologist by any means, and have not read research papers for this event, but in regards to the discussion of deviant motion and tornado width increase, a thought I am having is: could there be some relation between the average angle between the rear and forward flank downdrafts (if that's a thing) and the "width" of the inflow region (thus contributing to increase in the inflow flow rate and/or the increase in tornado width?)...or something else? In looking at the slide at about 45:00 in the video, the "average angle" I guess you could say between the main forward and rear flank downdraft seems to increase a bit from 2307:35 to 2310:44....and after 2310:44 is when the widening of the tornado happens...just a thought I had.

[@ConvectiveChronicles]

Thank you! Hmmm, interesting idea, one that I haven't thought of before. My hypothesis of the mechanism behind a tornado's size change is that there's an increase in streamwise vorticity ingestion; i.e. a large area of favorable "spin" that the tornado encounters that allows for a lot more vorticity to be concentrated within the low-level mesocyclone, hence perhaps causing widening of the tornado. That source could be a streamwise vorticity current (SVC), remnant surface boundary, etc. Your theory is interesting and perhaps a lot simpler...you can also see at 45:00, the 2314:09 box has a lot larger of a "cocoon" - i.e. the area or interface between the FFD and RFD - than the previous times. Perhaps a change in that angle you mention does something to change the size of that interface, creating a larger area for the vorticity concentration within the mesocyclone to occur.

[@Asterra2]

I'd be keen on eventually seeing a detailed analysis like this one that also happens to include the mesocyclone perimeter for reference. I've seen a few clips from time to time that show tornadoes that seem to more or less take their meso completely over, and a tornado reaching this width has me wondering. I'm also very curious about whether this tornado developed the classic "eye", or conspicuous area in its center of very low reflectivity, typically seen in mile+ wide tornadoes, and how the long-lasting center subvortex discussed in this video relates to that. Last thing I'll note is something that harkens back to the classic "Tornado Video Classics" video from the early 90s. A brief mention is made of "twin suction vortices" that Dr. Fujita claimed to have spotted in the film of the Xenia tornado. Well it just so happens that there's a certain clip of the El Reno tornado that legitimately and unambiguously reveals this phenomenon-a subvortex that's made of two vortices spinning around one another. I've long suspected that nobody else ever noticed this.

[@matthewwinter1340]

This was a fantastic analysis; I think the data used for drawn conclusions here are as good and effective at narrowing down the reason for the seemingly erratic behavior of this tornado, as what I've read from PhD mets and others. Just truly great data-backed and objective analysis. Somewhat of a disclaimer; Tim Samaras was my biological father (discovered this truth in 2006), and I haven't been able to bring myself to study this event until a couple years ago. Once I began studying this, I could not get enough of the meteorology and the physics behind it. I know that Tim, Paul, and Carl would have wanted this type of intensive studying of the physics of this event. But thanks again for the great, data-backed analysis here and references to peer-reviewed works! Looking forward to others on the horizon including May 20, 2013 Moore OK, perhaps Greensburg KS EF5, Parkersburg IA in 2008, or even way back to the Palm Sunday Outbreak in the 60s.

[@ConvectiveChronicles]

Thank you so much for the kind words, Matthew. I am very sorry for your loss; the weather community certainly got a little dimmer with his passing. The way to honor the legacy of Tim and his crew is to continue to rigorously study these incredible phenomena, and I know they would've enjoyed seeing the advancements to tornado science and forecasting made thanks to their work and the work of others post-El Reno. Thank you again; all of those case studies you mentioned are on my list! In fact, I'm planning on using Greensburg as my next one.

[@VASHtheSTAMPEDE_]

Just watched a couple videos on the el Reno 2011 tornado. Both of the el Reno tornadoes had the darkest clouds with waves of rain wrapping in like an inland hurricane.

[@dsz2448]

Love these analyses Trey! I’ve learned more from this channel than I ever thought could be possible. Question - does it seem to you like there was an unusually high amount of positive lightning with this storm? Maybe I’m wrong, but with all the videos of El Reno I’ve seen, there just seems to be a ton of those quick bolts with that almost whip-like crack of thunder - more than any other storms I’ve seen videos of. Would love to get your thoughts!

[@ConvectiveChronicles]

Thanks so much! I can’t speak to anything quantifiable regarding positive lightning on that storm, but those large CAPE days often do produce some epic lightning.

[@dsz2448]

@@ConvectiveChronicles yes, if I’ve learned one thing from these case studies, it’s that high CAPE/low shear is never ever to be underestimated. Thank you Trey!

[@lukeanderson4602]

Wow, amazing breakdown of this tornado!! I found myself in awe multiple times with the data and nuances that I'd never realized with this tornado. One question: do you think the merging of the parent vortex with the satellite could've had anything to do with the rapid widening and increase in speed? It seems to happen around the same time, so I'm curious. Once again, great video! I love that I found your channel, and keep up the good work!

[@ConvectiveChronicles]

Thanks so much! That’s a great question; I’ll be honest, I’m not 100% sure. There easily could be some vortex interaction there, perhaps some sort of Fujiwhara-type situation going on, which does tend to yield a larger vortex after the two original vortices merge.

[@lukeanderson4602]

@@ConvectiveChronicles Thanks for the response! That's really interesting. It's what makes weather so fascinating and frustrating to me at the same time 😂. So many things that could've led to something happening, but it's so hard to pinpoint what it is because there's so many different variables at work!

[@ConvectiveChronicles]

@@lukeanderson4602 Couldn't agree more!

[@rox1180]

Been waiting on this one

[@danielwieten8617]

I’ve had math through differential equations and a lot of this analysis still makes me feel dumb lol. Great stuff though, man. The amount of work you put into it is extremely admirable and impressive.

[@ConvectiveChronicles]

Thank you for the kind words!

[@Hayden2002WX]

Oof, diff eq

[@asii_k]

I was literally just looking for something about El Reno to watch 15 min ago

[@johnned4848]

Fantastic case study. Need to re-watch but was especially interested in the early/ pre initiation stage of the storm. According to book about Tim Samaris, the OKC area was getting bombarded on a nearly daily basis with storms and potential storms ( including the EF-5 Moore a few days before). It spoke about the unease at the SPC the day before when similar conditions were observed but no tornado. So they watching closely on the 31st. They held off on issuing warnings but were in close discussion with local media and government throughout the day about "pre-warnings". And then around 3 o'clock the SPC head has his " oh shit" moment when he's outside and the wind direction shifts 30 degrees S to SW which told him the dry line had just moved. And from your video the convection cap was gone and explosive growth was,now commencing. That's actually the part I'd love to see more footage of. Again great post. Fantastic job.

[@ConvectiveChronicles]

Thanks so much! Yeah, this day was the end of an insanely active stretch for Oklahoma, with the Shawnee/Edmond/Carney tornadoes on May 19, the Moore EF5 on May 20, a squall line on May 21, and the threat on May 30. No wonder forecasters were uneasy, especially with these parameters coming together and the low-level winds shifting to a much more favorable setup in the afternoon.

[@johnned4848]

@@ConvectiveChronicles thanks for getting back! What was, the critical difference between the 30th and 31st. It sounds,like it was almost there on Thursday- yet no one can predict it until it happens. And if it had gone off on the 30th, would it have been as powerful?

[@ConvectiveChronicles]

The key difference on the 30th was a slightly mistimed shortwave moving through before parameters were maximized. Some slight subsidence was noted on the back side of the trough, which kept storm coverage/sustenance at bay. There were a few storms that went up due to strong sfc heating, and there were several severe reports, but nothing like what it could’ve been. The 12 Norman sounding sampled a very intense environment with very strong shear, deep low level moisture, and strong instability. Would’ve been a significant outbreak had the shortwave been timed right.

[@johnned4848]

@@ConvectiveChronicles thanks again! Shows why tornados are so difficult to predict and analyze. Lotsa moving parts that have to be in synch.

[@johnned4848]

@@ConvectiveChronicles one further thought on this. So it sounds like there was a loaded gun on the 30th, but the trigger didn't get pulled. So conditions basically remained in place overnight. Possibly slightly cooled overnight. But still the next day no guarantee it will go off until that afternoon when the dry line shifted. And with a loaded gun, conditions were ideal for large and violent storms although the scale surprised everyone. I makes me think that the theory behind tornadoes at the mathematical physics level maybe needs to incorporate something like chaos theory- how small events can have outsize effects. The Jarell tornado seems to be a similar case. The conditions weren't ideal but small anomalies produce a monster late in its life cycle. It seems that high CAPE and low wind shear were common factors. I'm wondering if there's any supercomputer modeling going on that uses chaos theory in tornado development.

[@onlyonecaca]

New subscriber. Keep up the great work sir!

[@ConvectiveChronicles]

Thank you!!

[@daver00lzd00d]

incredible video on an incredible event

[@ConvectiveChronicles]

Thank you so much!

[@daver00lzd00d]

@@ConvectiveChronicles no sir thank YOU for putting all the time and energy into this stuff. you're a blessing to those of us who are too math challenged for a meteorology degree lol

[@cfbisbetterthantheNFL]

Around 22:30 you talked about why the Tornado became rain wrapped. Could you explain further why weak outflow winds in the mid-level allowed for that to happen? How does stronger outflow winds cause an LP supercell? Are we talking about the RDL here? I’ve always been confused how LP vs HP supercells form and would love some clarity. Thanks in advance!

[@ConvectiveChronicles]

Strong storm-relative outflow winds help to push, or vent, the precipitation in the mid-levels away from the updraft/mesocyclone region of the supercell, which helps make any tornadoes that occur more visible and can yield LP supercells. In contrast, when you have weak storm-relative outflow winds, the precipitation is not vented away from the updraft/mesocyclone region of the supercell. Thus, the rain falls very close to or within the mesocyclone area of the storm, which yields a more HP storm and obstructs the view any tornado that may form. I hope this helps; let me know if you have any other questions. You can also get some more info on these processes at the following link, just scroll down a bit to the "Storm-Relative Wind" section: cameronnixonphotography.wordpress.com/research/the-storm-relative-hodograph/

[@cfbisbetterthantheNFL]

@@ConvectiveChronicles that totally makes sense, thank you so much for answering!

[@obsidianwing]

Wow this was a very in deepth analysis, very intressthing. I was minblown by the research of the Anti Cyclonic MV Tornado in this monster.I never thought this would be even possibible.

[@ConvectiveChronicles]

Thank you for watching!

[@phAntasyluvr_04]

I didn't realize they formed the EF scale as early as 2001. Very interesting! I get, now, why it wasn't rated an EF5. That 3 second technicality is kind of similar to how blizzards how determined.

[@hgbugalou]

Are there surface temperature/dew point or VT maps available slice by slice with the dow data? I have never seen mesonet type data with this in a map form. I'm guessing the resolution would be too sparse this zoomed in with that many frequent time slices. I've always been curious if this event could have been a psuedo warm seclusion like event we see with larger tropical systems just on a much smaller scale, namely the strengthening and loop de loop behaviour post occlusion.

[@ConvectiveChronicles]

Unfortunately not; the mobile radars aren’t equipped with instruments to measure those environmental variables, and there isn’t any source that measures those variables on that time scale. The Oklahoma Mesonet would be closest, but it still isn’t as high resolution, both in time and space.

[@hgbugalou]

@@ConvectiveChronicles Yeah I kind of figure that seeing as how you would need probes ever km or more to pick up things on this scale. Hopefully the work Leigh Orf and others are doing will allow us to plug in variables and run a model that is accurate to nature pretty soon.

[@brianwise5850]

you were discussing tornado genesis where there are two methods, one descending and one ascending. my question is, in tornado families is it more common for it to be a descending tornado genesis, or is it ascending. also is it likely that just the initial tornado in a family would be an ascending tornado, then all following tornadoes to be descending, or could there be a mix of them?

[@ConvectiveChronicles]

So unfortunately, those are questions we just can't answer yet. I don't think it necessarily has to do with whether or not it's a tornado family, it probably has more to do with the environment. But, we don't have enough datasets from enough storms to really know the answers. Tornadogenesis mechanisms are often only able to be resolved with high-resolution mobile radar, and I can tell you from experience, actually getting a dataset that goes from just before to just after tornadogenesis is tough. Hopefully, more research will be done on the future on this topic.

[@ThunderChasers]

just thinking about bottom-up tg. In most of the cases that I can remember, being on the ground, there was a sudden ramp-up of winds before tornadogenesis. I witnessed it most prominently in the Madill tornado a few years ago. in another case, where a tornado ultimately did not form, there was no ramp-up in winds. just a steady light breeze.

[@joseph-frankbrocchus6575]

This is another one of your great videos that I really like looking at/I am glad that you covered the part about the floods in Oklahoma City because I had friends that while they were not affected by any tornadoes had a lot of flood damage/thank you for your hard work

[@ConvectiveChronicles]

Thank you so much! Yeah, the flooding was perhaps even more impactful than the actual tornadoes.

[@joseph-frankbrocchus6575]

@@ConvectiveChronicles Thanks for answering my question / I know you get lots of suggestions for videos, so this is not really a suggestion, but just in your spare time just to read about “ ancient” storm and tornado events, look up April 12, 1945, May 5, 1960 and May 5, 1961 / believe it or not that’s not a typo one year apart events // thanks for your kindness and expert knowledge

[@ConvectiveChronicles]

@@joseph-frankbrocchus6575I will check those events out; thank you!

[@joseph-frankbrocchus6575]

I just discovered something interesting about the April 12, 1945 outbreak in Oklahoma and surrounding states/that was the same day that Franklin D Roosevelt died and it mentioned the next day the papers had to balance between the headlines being about the severe weather and President Roosevelt/I am a subscriber, and “like” any of the videos I have seen

[@ConvectiveChronicles]

@@joseph-frankbrocchus6575Wow, that's pretty crazy!

[@colin7244]

Already know this video is fantastic but also I am curious if you could do a case study on the easter outbreak since that one im kinda confused on why the event was so prolific and the amount of tornadoes especially at night

[@ConvectiveChronicles]

I take it you're referring to the April 12, 2020 outbreak (Bassfield EF4)? If so, that's on my list.

[@colin7244]

@@ConvectiveChronicles not just that tornado but all the other significant ones especially during april 13th

[@hopbup7401]

My bad I thought the yellow line represents the center of the tornado not subvortex path. All those vortices popped up around Twistex. I wonder if that’s why they couldnt reverse. 1 was behind them too.

[@ConvectiveChronicles]

The subvortex was just moving so quickly that they had almost no time to react.

[@jamescinman1993]

This may be a dumb question but I'm gonna ask anyway. Can major highway projects (dealing with flattening the land) in conjunction with natural weather patterns exacerbate tornadic activity? In particular I'm curious about the path most of these major tornados take in Oklahoma in regards to i44.

[@ConvectiveChronicles]

No, that’s (as far as we know) mostly a coincidence.

[@davidspangler4430]

In jim bishops footage of the el reno tornado, between 16:52 and 17:00 in the video, u can see headlights about a third of the way up the tornado, move across the tornado aloft. The time was around 6:23 or so. U can see a large sub vortex on the right side of the tornado and as it wraps around u see the headlights. It takes less than 10 seconds for the vehicle to fly all the way across the main tornado. Seems to match up with the timing of a certain groups last moments. Its unreal watching the video knowing what happened at that time, especially seeing that subvortex wrapping around, just like the radar and studies show. Thank you for these videos

[@ConvectiveChronicles]

Yeah, that footage is pretty crazy. Can't say for sure whether that is the Samaras group's vehicle or not, but evidence does suggest that it could be.

[@davidspangler4430]

It amazes me that this footage doesn't get more recognition. If we assume that is a vehicle aloft, then that should be proof of ef4+ winds and damage, I believe it take ef4+ winds to keep a vehicle aloft. Thank you for these videos

[@adstalga]

I've seen video of this one. Outside the subvortices, how come it's hard to tell one is actually inside the tornado? Is it because of the shear size?

[@ConvectiveChronicles]

Yeah, it was just so big with such a wide wind field that it was hard to tell.

[@jacekatalakis8316]

Given both the 5/20 and 5/31 tornadoes did or tried in the case of the 5/20 one, occlusion loops, is there anything noteworthy that'd cause that in the geography of the OKC area and the OKC metro? I'm always fascinated by unusual tornado movements, and I thought you covered other ones in the past, I need to go check and see if you did0

[@ConvectiveChronicles]

Usually those loops are going to be the result of occlusion of the mesocyclone, which occurred in both the 5-20 and 5-31 cases. This paper goes into really good depth on the Moore tornado's loop and what caused it: journals.ametsoc.org/view/journals/mwre/143/7/mwr-d-14-00357.1.xml?tab_body=pdf Frictional effects from buildings and such in big cities like OKC can cause shifts in the intensity, appearance, and track of the tornado, but most of the time, loops will be caused by processes within the storm.

[@jacekatalakis8316]

@@ConvectiveChronicles Ahh, the buildings don't afect it as much as I thought they did, that makes sense. For some reason I assumed buildings would have a stronger impact on the tornado itself, I'mnot sure where I got that from, probably from a poorly designed building over here that did this but on a larger scale up to and including a major wind tunnel effect. I think I just got my wires crossed with that and tornadoes being afected by buildings in big cities. That's a really interesting paper, I'll bookmark it and read it in bits

[@hgbugalou]

Is there any correlation with high cape/low shear and ascending tornadogenesis and vice versa? I think tornadogenesis can and does happen both ways depending on condition variables.

[@ConvectiveChronicles]

So that is one of my hypotheses. In my master's thesis, I looked at four different events w/ high-res mobile radar data. Found ascending tornadogenesis in the Elmer, OK case (shown in the video) and descending tornadogenesis in the 6-15-19 Putnam, OK case. The former was a higher shear case, while Putnam was a much weaker shear case. Obviously it's a small sample size, but there may be some merit to that hypothesis.

[@hgbugalou]

@@ConvectiveChronicles You should do a video on your thesis sometime! I would love to hear about it. Also do you have a link where I could read it?

[@ConvectiveChronicles]

@@hgbugalou That's a good idea, I might! Yes, here's a link: shareok.org/handle/11244/330737

[@plawson8577]

@@hgbugalou This 2 Mile wide Monster was an unpredictable and complex Tornado. It was like it was designed to kill Storm Chasers. Twistex died because they were Unable to get to Safety when the Sub-vortices suddenly changed direction and snagged their Chevy Colbalt.

[@Achronym]

​​@@ConvectiveChronicles hi Trey, I was looking at your thesis paper and I was just wondering, how long does it take to research and then write those?

[@fabianbuserell8609]

At 52:50 u mentioned that the tornado has to deviate back to the north because the tornado initially turned south east. To my untrained eye the speeding up of the tornado happens to be at around the time it is going back up north trying to follow the apparent storm motion. can this be some something like a slingshot, since the storm base and top levels are connected and the tornado is getting pulled?

[@ConvectiveChronicles]

That's an interesting question that's hard to know for sure...I think the change in speed had some other factors that went into it, but that's an interesting proposition.

[@jadefox5285]

I miss that video that showed all the footage of the separate storm chasers, it had mesmerizing shots. Did they ban it?? I cant find it....

[@ConvectiveChronicles]

I'm not sure; could be a copyright issue if it's an aggregation of a bunch of others' videos

[@jamessimon3433]

Hey I have a quite stupid question. I use radarscope and I noticed in the velocity radar product I sometimes see totally black pixels. Sometimes directly adjacent to the colored ones. Are these just artifacts or where the beam gets no reflector data to display? Does velocity maps alias?

[@ConvectiveChronicles]

They are most likely bad pixels that were taken out during the quality control process before the end product gets displayed on the app. The data goes through extensive massaging before the final product gets released, including dealiasing velocities (we see the final product after the aliased velocities are unfolded).

[@jamessimon3433]

@@ConvectiveChronicles Im sorry to take advantage of your time but are there any textbooks you would recommend for introing meteorology? Is there a "bible" for meteorology? You clearly understand and can effectively teach the thing. Plus you ACTUALLY respond to your subscribers. If you had any recommendations that would be amazing. Either way Im going to contribute to your channel.

[@ConvectiveChronicles]

@@jamessimon3433 Don't apologize! Always happy to help. As far as books/textbooks go, it depends on what your interests are within meteorology. A lot of the college textbooks out there are not that well written (speaking from experience)...If you are just starting out and want to know the absolute basics of the science of meteorology, I would start with the online NWS Jet Stream modules. They are such a simple but comprehensive intro to meteorology that anyone can understand, even with little experience: www.weather.gov/jetstream/ If you have a base understanding of weather and your interest is more severe weather/severe weather forecasting, I would start with Tim Vasquez's awesome handbook series. All of the books are great, particularly the Severe Storm Forecasting Handbook and Weather Analysis & Forecasting Handbook: www.weathergraphics.com/books/

[@SShrikke]

With this initial southeasterly track, I find it hard to believe that this tornado strengthened with purely crosswise vorticity at the surface

[@SkilledLegend]

Would love to see someone look at the 2004 Hallam, Nebraska tornado and see how it compares to this as they both were extremely wide tornadoes!

[@ConvectiveChronicles]

It’s on the list!

[@Lessinath]

I have a suspicion that both ascending and descending tornadogensis are possible, however, they arise from different (but similar) conditions. I also suspect that the overlap between these means that you can have the same storm potentially produce both kinds at different points in its life, as it moves into different conditions. However, from personal experience I get the impression that ascending tornadogenisis might be more common, just from experience. There's been a ton of times chasing that I have seen a swirl of dust or leaves under the mesocyclone often many minutes before any kind of tornado strength winds are present. I have no idea if this is the start of a surface vortex, or just transient concentrated vorticity, but I know I've seen it often enough that it doesn't seem like chance. I'm not *super* confident in this, and I don't know how one would begin to prove it, so I'd like to hear your thoughts on this. (Or anyone's thoughts, really.)

[@ConvectiveChronicles]

Completely agree! In my thesis, I analyzed four different tornado cases using high-res mobile radar data, and I found evidence of both descending and non-descending (ascending) tornadogenesis among the cases. The Putnam, OK tornadic supercell on 6-15-19 appeared to feature descending tornadogenesis, while the Elmer case appeared to feature non-descending tornadogenesis. The former case was a lower shear event, while the Elmer case was a much higher shear event. Of course, small sample size, but perhaps that has something to do with it; regardless, I do think the environment has a lot to do with the method of tornadogenesis in storms. I also agree that ascending/non-descending tornadogenesis may be more common; we just don't have a big enough data archive of tornadogenesis cases from mobile/high-res radars to make a definitive statement. But I too have seen a lot of cases out in the field where the tornado does seem to begin with concentration of vorticity near the surface which works upward with time. Very interesting stuff, and hopefully more research will be done on these topics in the future.

[@gl3618]

Could you do the Albany GA EF3 tornado? Been curious how such a strong cell remained strong in a squall line filled with short-lived rotations. Long track EF3 with a lot of size and intensity changes throughout it's life.

[@ConvectiveChronicles]

What was the date?

[@gl3618]

@ConvectiveChronicles Jan 22, 2017. Came from a squall line (of many that day and before) but was long track and very strong for that time of year and it not being from a discrete cell. I believe it was a strong rotating cell within the squall line. Hit mobile home parks in Albany bad. Several tornadoes and warned storm have followed nearly identical paths over time, from Leesburg south to Moultrie area. Worth County is especially a hot spot due to its height in miles and location, like NW GA counties.

[@gl3618]

@@ConvectiveChronicles I've got a few short videos of the approaching rotation and one from inside a home where it passed 1/4 from us near its widest point.

[@ConvectiveChronicles]

@@gl3618Ah, that's right. I do have that day on my list, but more so to analyze why the High Risk seemed to underperform in general, despite a couple stronger tornadoes like the Albany one.

[@gl3618]

@ConvectiveChronicles crazy day. I booked it from Dothan Alabama to the area of Harris road you'll read about with that tornado, 30 mins before it hit. Had reserve duty that weekend and convinced command to let us all leave a little early. Entire storm was rotating with it. I can email you the short videos I have, almost got struck just before it appeared as a wall of clay behind some trees. Sadly my video from inside is brief because we turned and went to a better place inside. Went white out conditions outside the window and we were maybe 1/4 mile from the visual funnel...that was a massive wedge.

[@jamesrousculp1974]

I like your videos and I wish you would do a case study of the 2019 memorial day tornado outbreak

[@ConvectiveChronicles]

Thank you; it’s on my list.

[@kendallowens8566]

You mentioned that the NWS measured a damage path at one point of 2.6 miles. Was the path continuous in it's width, or was some of the the damage within that span created by satellite tornadoes? Because as you said, a satellite tornado is a separate tornado. I guess my question is, " Was there ever an actual 2.6 mile wide funnel on the ground?

[@ConvectiveChronicles]

The tornado was not continuously 2.6 miles wide, but it was at its largest point. There wasn’t necessarily a funnel 2.6 miles wide at that time, but the tornadic circulation was that far across.

[@retrofoxartandgaming5578]

I had just left el Reno when this happened my sister had a dance competition there I remember it had gotten canceled due to weather and we decided to just head home as native okies we didn’t think much of it I remember being in McDonald’s as it was going on just outside of town it’s very surreal thinking back on it but I didn’t know what was going on I was probably 9 or 10 used to live deep in tornado alley but I live just outside of it now but I guess my town did get hit last year so I’m not too far out of it. One my first memories as a child is watching a tornado cut across my neighbors field it was a weak one but me and my dad sat right outside the storm shelter and watched it it was breathtaking. It’s crazy how something so beautiful can cause so much damage and pain everyone I know has been touched by the weather in some way but I wouldn’t live anywhere else.

[@dillyboyq]

The straight loopty loop that the path took is so insane to me. I’m sorry if you say why it did that in the video, I’ve just started watching and haven’t got there yet! But If you don’t talk about it in the video, can you tell me what causes it to take that crazy loop of a path?

[@ConvectiveChronicles]

So that was the result of a "failed occlusion." Usually during an occlusion, the rear-flank gust front chokes off the tornado circulation from the warm/moist air that's feeding it, and it detaches from the parent mesocyclone. That generally means the tornado moves to the left of the mean flow and is about to die off. However, in this particular case, that didn't happen; instead, the tornado restrengthened and regained its path toward the east, as a mature tornado would do.

[@dillyboyq]

@@ConvectiveChronicles thank you for the answer! I couldn’t imagine being a chaser and having to deal with that and trying to plan for that. Great video as always!

[@ConvectiveChronicles]

As a chaser, I can tell you it can be very difficult. In these extreme CAPE scenarios, you just have to give the storm space, as all rules go out the window. Thank you again!

[@kainhall]

0:01 that Malta MT supercell was something else..... . MT can get storms like that.... but not that often (especially in the last ~5 years.... everything just goes QLCS)

[@ConvectiveChronicles]

Yeah, that was the structure of the year for 2021. Love chasing in Montana; I've seen some incredible storms up there.

[@kainhall]

@@ConvectiveChronicles I live in glasgow/fort peck area . I was watching the Malta storm on radar and cussing because my boss would not let me leave 4 hours early LOL . . But ya.... some crazy storms up here Also had a storm turn 90 degrees, head straight south right over my shop . TONS of low level rotation . Also had quarter size hail, but they were flat... not round . Very strange . . Lost all the pics and videos of that storm when I broke my phone sadly

[@ConvectiveChronicles]

@@kainhall Last year was my first experience chasing in Montana, and I loved it. Can't wait to get back up there soon.

[@LordOstrik]

I have been questioning why on Earth this tornado was rated EF3 for years. While I still firmly believe that any tornado with an observed measured wind speed of 250mph or higher near the ground should be EF5 by default, thank you for explaining the reason the storm is rated the way it is.

[@williamtrakas3142]

You’re the best dude!

[@ConvectiveChronicles]

Thanks so much!

[@CH_eatthesand]

I'm by no means educationally endowed on physics relative to the study of meteorology but knowing the driving mechanism vs the forming mechanism of storms like this, it makes far more sense that the circulatory genesis begins from the ground up. You have inflow and updrafts feeding the storm, and winds at various heights and directions aiding it, and the storm essentially dropping cooled air down around it, also being steered about. Sooner or later, those pools are going to cinch up very quickly. I see this in dust devils in the Southwest all the time. Cooler air will displace hot air, right?

[@ConvectiveChronicles]

It is certainly true that cooler air displaces warmer air, but the colder downdrafts are just one small part of tornadogenesis. Tornadogenesis is a delicate balance between the (ideally) warm rear-flank downdraft, the warm/moist inflow, and the cold outflow from the forward flank precipitation core. Too much cold air will undercut any developing mesocyclone and nix tornadogenesis. Whether or not tornadogenesis first occurs at the ground or aloft has to do more with the dynamics/physics ongoing within the storm, and that probably is modulated by the environmental characteristics.