The Moore, OK, EF-5 Tornado of May 20, 2013: A Case Study 

Thank you! This one and the 1999 EF5 within a 15 year span…Moore does have some bad luck.

​@@ConvectiveChroniclesI would not be surprised if they got another big one within the next 10 years, although May seems to perform well below average lately when the tornado threat shifts westwards

Only a matter of time before it happens again..

That's why Tornado prediction is SO hard. All these small scale things can make a huge difference to intensity of vorticity.

Thanks so much! Totally agree!

When “all it takes is one storm” is taken into a meaning both in the meteorology of what happened when the small storm cell merged with the large cell making the shear go nuts and how that storm was the only storm that had a drastic impact on people’s lives that day

Both on my list!

@@ConvectiveChronicles Badass. And thank you for the fantastic content you create!

I remember that day in 2016. Was watching the radar out of Detroit after getting reports of tornadoes near Toledo, Ohio - then the action moved into Windsor, Ontario. Had to phone a friend, whose family lived near Windsor to tell her about the potential tornado, as Environment Canada didn't issue a Tornado Warning until after the tornado (EF2) had lifted!

April 2-4, 1974 is so unique. Again, F3 tornado impacted Windsor, Ontario, badly damaging a curling club building.

Thank you!

Thank you! Yeah, I’ve seen a lot of cases with failed occlusions. Would love to know more about why the occlusion process can fail sometimes but other times it’s successful.

Thank you so much for the kind words!

Dang, nice!

Thanks so much! I agree!

@@ConvectiveChronicles Your welcome.

That’s all thanks to the hard work of Broyles and company at the SPC. Really intriguing stuff, and it’s something that may influence more violent tornadoes than we think.

Thank you so much!

Thanks so much!

@@ConvectiveChronicles Being an aviation enthusiast and weather nerd, is there enough scientific data surrounding the microburst crash of Delta 191 in 1985 to do a case study on and the affects it had on the weather and aviation communities?

@@sythemaster1Yes, that would be an interesting one to do!

Thank you so much!

So true. The Joplin EF5 might have grown more rapidly in sheer size. Still, the Moore EF5 became super intense very quickly, almost immediately producing strong to violent damage, even during its cone and stovepipe phases, much like the F5 that occurred in 99. Horrifying events.

A lot of people have asked why the Joplin, Missouri tornado on May 22, 2011 was so much deadlier than the Moore, Oklahoma tornado on May 20, 2013 even though they were both rated as an EF-5 by the National Weather Service. It comes down to the following six key factors: 1.) The Joplin tornado formed too quickly for the National Weather Service office in Springfield, Missouri to issue a Tornado Emergency for the city of Joplin even though they had issued a Tornado Warning for both Jasper County and Newton County. 2.) The tornado formed right outside of Joplin, cut through the city and dissipated upon leaving it. 3.) Prior to May 22, 2011; Joplin had not been hit by a significant tornado since May 5, 1971. As a result the residents of Joplin, Missouri assumed that the mountainous and hilly terrain of southwestern Missouri functioned as a natural shield from tornadoes as southwestern Missouri is home to the Ozarks. 4.) Many residents of Joplin ignored the tornado warnings when they were first issued due to being desensitized from the city issuing too many false alarms. 5.) When the tornado sirens in Joplin were first sounded at 5:17 PM Central Time it gave the residents of Joplin a woefully insufficient amount of seventeen minutes to take shelter. By the time the tornado sirens began to sound a second time at 5:34 PM it was too late to do anything because the tornado was already on the ground and moving through the city. 6.) By far the biggest contributing factor is that the Joplin tornado was hidden by heavy rain and difficult to see. By comparison the residents of Moore, Oklahoma are extremely weather-wise and aware of the potential severity of a tornado as their city is practically synonymous with large, long-track, violent and destructive tornadoes. When a Tornado Watch is issued the residents of Moore become extremely vigilant and keep their eyes on the sky. As soon as a Tornado Warning is issued the residents of Moore know to stay calm in order to make smart decisions that will save their lives. They know what to do and where to go as well as who they can turn to for coverage of the weather. When the National Weather Service office in Norman, Oklahoma issued a Tornado Watch for much of central and eastern Oklahoma at 1:10 PM Central Time three of the major TV stations in Oklahoma City (NBC affiliate KFOR channel 4, ABC affiliate KOCO channel 5, and CBS affiliate KWTV Channel 9) immediately suspended regular programming and went into wall-to-wall coverage of the weather; with the city's Fox affiliate KOKH Channel 25 and Telemundo affiliate KTUZ Channel 30 doing so when the first thunderstorms erupted southwest of Oklahoma City.

Thank you so much! I was really happy with how this one turned out; I’m trying to structure these a bit better so they’re more concise but still pack all the info into a single video.

Thank you so much! I was really happy with how this one turned out; I'm trying to make these more concise but still pack the same amount of info into each video. The storm certainly had the "perfect storm" of nuanced ingredients to go from a run-of-the-mill severe weather producer to a historic one. It's not often that that's the case AND we have incredible tools there to measure, it like the super-high-res PX-1000 radar only a handful of miles away. And I am with you on failed occlusions...hopefully, we get some more research on them in the future.

Thank you so much!

Thank you!

Thanks so much!

Thanks so much! Absolutely agree; these events are awful when they impact people’s lives, but the best thing we can do is learn from them to be better prepared.

Thank you!!

Thank you so much!

Thank you!!

Thank you so much!

Thank you so much!

Thanks so much, Ethan!

@@ConvectiveChronicles You're very much welcome!

Thanks so much!

Thanks so much!

Thank you!

Thanks so much! I’ll add it to the list!

April 16 2011 Carolina outbreak, a strong squall line entered n.c. And low level jet ripped apart the squall line and all became discrete supercells

Thanks so much!

Thank you so much! I really appreciate it!

Thank you! I'll be completely honest, winter weather is not my forte, so I tend to shy away from doing these full-fledged videos on winter stuff.

Thank you!

Thanks, will do

Great suggestions!

Thank you!

Thank you! Yeah, 2013 was a crazy year for central Oklahoma, really just that 2-week stretch in May. One of the most nuts periods in recent memory.

Thanks so much! It’s always tough; in a lot of cases, terrain can be the driving factor (e.g. Colorado/Wyoming) and you don’t need a ton of synoptic-scale forcing for ascent, whereas in other areas, you need a stout synoptic system to kick things off.

Thank you! It's on my list!

Thanks so much!!

Yeah, Moore has had some bad luck over the years…thankfully, I was not living in Norman at the time.

Not only Two cat 5 tornadoes on the Fujita and Enhanced Fujita scales respectively, but two of the most violent tornadoes ever recorded in history as well. We know how destructive May 3rd was. Hell, the EF5 category was built upon that tornado and Jarrell. However, I know people are going to rip my face off for this, but the May 20, 2013, Newcastle Moore EF5 was every bit as violent as the 4.27.2011 tornadoes (the NWS themselves think so too). This tornado produced many of the same DIs that the Phil-Campbell Hackleburg and Smithville EF5s did. Want to know 3 tornadoes that ripped out and completely shredded electrical routing and plumbing out of many foundations? Smithville, Jarrell, and this tornado, the Newcastle Moore EF5. It's a tale of just how extreme an EF5 tornado truly is and it's a sobering reminder that any strength disparity between one EF5 and another is paper thin at best.

Another one that was close was the Rochelle/Fairdale IL EF4. An estimate of 200 mph winds was given with that one. That one I believe would have been an EF5 had that one hit a larger city rather than remaining in rural farmland

I think the southernmost cell was able to take over just because its inflow was unimpeded. The northern cells had storms that were influencing their inflow, whereas the southern storm had a much cleaner environment to work with.

Haha thank you so much!

Yes, Windsor is on my list

I like you❤ I was thinking the same thing! 😂

First of all, thank you for being a new subscriber, and I'm happy to hear you're enjoying the videos! The threat for strong tornadoes certainly was there, as it is in a lot of highly unstable environments. However, the wind profile was not all that favorable for violent tornadoes; as I explained in the video, unique storm mergers and dynamics were the main reasons for the Moore tornado. Most of the other storms in the OKC area and southward didn't do much of anything because they didn't have the right storm interactions to bolster their proximity environment, which was less than ideal to begin with and needed those storm interactions to compensate. I'll be 100% honest, I don't have a very favorable opinion of Mike Morgan...his antics during El Reno 2013 aside, I've seen him call for significant tornado outbreaks numerous times when the setup is clearly not even in the same ballpark, and nothing of note happens. As far as Reed goes, he even ditched the OKC area to target storms to the south and missed the Moore tornado. These highly unstable environments have extremely high ceilings, even with limited wind profiles (examples are the 1997 Jarrell, TX F5 and the 1990 Plainfield, IL F5, both which I've done case studies on), but everything has to be absolutely perfect (boundary/storm interactions, etc.) to bolster the environment and get violent tornadoes. So I can see why the concern was there ahead of time, as it was a very high-ceiling, very low floor event, and these TV mets know, especially after May 3 1999, how important it is to have folks prepared for the worst.

@@ConvectiveChronicles To be honest I don’t have a very high opinion of Mike Morgan either, especially after the May 31st debacle of telling people to leave town. That being said although he tends to overhype, especially in the past, he has also made some very good calls and does have a lot of experience and local knowledge in this specific market. I might be showing my age here as a 40 year old, but I think experience is something people don’t value as much as they should. Knowing the reputation Mike Morgan has is why I also include Gary England, Reed Timmer, and the video of the meteorologist at the NWS that told his daughter to leave town that morning. Your response to my question just reaffirmed why I asked it and didn’t answer it at all. I know that patterns and every other meteorological things you said are true, and even though Mike Morgan can be a littler hyperbolic sometimes the way he talked that morning is something I’ve only seen him do maybe 10 times in 30+ years and Gary England do a few times at the most. Not something you would do on an unremarkable day. I also just watched an actual RU-vid video from the National Weather Service from 11:00 am that day that said the exact same thing. So my question or confusion again isn’t what were the synopsis of that day, it’s why when I look back at multiple local sources from that day do they say long track violent tornado’s are likely, but when we go back to analyze it we see something different? This is not an opinion, this has been proven by multiple sources including local meteorologist that are hyperbolic, local meteorologist that know more than any of us will forget and under hype many times, and the meteorologist at the National Weather Service that issued the Tornado Emergency 16 minutes before the tornado hit Moore. This guy who has all of the credentials you could want, that lived in Moore, told his daughter that morning to leave town. Most important my own memory from this all stemmed from. I don’t claim to be on your level in any way, but I am from the generation that went to see Twister for a field trip in 7th grade, lived in SW OKC on May 3rd, and am a hobbyist and storm chaser. I went through the eye of hurricane Laura, I’ve witnessed 20 tornadoes, and I’m flying out to Donner Pass tomorrow morning for the 10 feet of snow this weekend. So it’s not just a passing memory. This was an important moment in my life. I vividly know the environment that was the morning of May 20, 2020. You can not tell me there was not something they saw that morning that completely contradicts everything you and every other meteorologist making videos about it today. They knew that morning that it was in fact a remarkable day, not the other way around. They in fact knew large violent tornadoes in OKC while schools were letting out was likely. Not my words, words from the National Weather Service in Norman. I’ve gone back and watched the videos, I’ve gone back and looked at many social media accounts, and It’s just doesn’t square with the post analysis. I’m not holding that against you, or saying anything negative about you or anyone else. I am just genuinely curious and I bet it would make a great video. Why did everyone in OKC seem to know that morning what was going to happen, but today people say nobody saw it coming?

@@danieljordan9004 The folks at the SPC, whose severe weather info should be trusted first and foremost, had a 10% hatched area out for strong tornadoes all through the event, the lowest probability level for which a hatched area can be added. They mentioned isolated strong tornadoes, nothing about long-track violent tornadoes. The environment was simply not a clear example of a violent tornado environment, as expressed in the video and by SPC forecasters that morning. Gary and Mike warning about violent tornadoes was probably based on "experience" working in Oklahoma for decades, but it likely did not have meteorological backing, as the meteorology was simply not there for violent tornadoes, at least until we could see storms interacting in real time.

We’ll see; we’ve had a few contenders over the last few years.

Absolutely! I believe that arc of lowered CC is debris fallout.

Yeah, that seems to be the classic corridor for some of the big OK tornadoes

🎉

The jet streak appeared to have locally enhanced the environment, and storm interactions certainly played a role. It might be a coincidence, but when the jet streak fully passed by and was no longer influencing the storm, the tornado seemed to begin its occlusion process

Can’t imagine what seeing that damage in person must’ve been like

@@ConvectiveChronicles It's not on my "Top Ten Days of Fun" list. I've lived in Oklahoma for many years and seen many tornados. This was the only one to scare me. (I was in Colorado for the May 3rd and didn't know until afterwards.)

It’s on my list!

Minor nitpick: the Parkersburg, Iowa EF-5 tornado occurred on May 25th, 2008. Not many people outside of Iowa know about it because it had only been a year since the first ever EF-5 tornado struck Greensburg, Kansas.

Yes, field soundings are an integral part of most tornado field campaigns.

@@ConvectiveChronicles does NWS archive and publish field soundings?

Unfortunately no

It's on my list, actually as a "failure mode" case study, as the tornado threat didn't materialize quite as expected.

Dang, sorry to hear that

@@ConvectiveChronicles Thank you it was terrifying. We had just paid off our truck May 3 completely totaled. He said before he ran into the bathroom the truck is coming 4 feet off the ground. I’m glad my neighbors and us were okay. Now I laugh about the truck. Especially when thinking children at Plaza Towers perished. The school was 3 blocks from us.

There's some complicated math that can explain this, and it helps to have an image to see, but I'll try to explain it in words: north of a jet streak's core is the region of maximum positive vorticity (cyclonic/counterclockwise spin), and south of a jet streak's core is the region of maximum negative vorticity (anticyclonic/clockwise spin). We can simplify the vorticity equation, which is one of the fundamental equations in meteorology, to show that the degree of vorticity advection is directly related to the degree of divergence. You can have two kinds of vorticity advection: negative vorticity advection (NVA), which is when the background flow transports negative vorticity into a region, and positive vorticity advection (PVA), which is when the background flow transports positive vorticity into a region. Assuming west to east flow through the jet streak, as is the case the vast majority of the time, we can determine that in the left exit region, we have strong positive vorticity being advected into the region, which is PVA and thus yields divergence. In the right exit region, strong negative vorticity is being advected into the region, which is NVA and thus yields negative divergence, which is convergence. In the right entrance region, we have higher (more positive vorticity) being advected into a region of lesser vorticity (closer to the max negative vorticity region south of the jet core), which is PVA and thus yields divergence. In the left entrance region, we have lower (more negative vorticity) being advected into a region of higher vorticity (closer to the max positive vorticity region north of the jet core), which is NVA and thus yields convergence. Hopefully, this helps; I wish I could include an image with this comment, as that would make things a bit easier to understand.

@@ConvectiveChronicles Wow, thanks a lot for the in depth explanation.

@@RafutahOf course! No, it has to do with the curvature in the flow in and around the jet streak.

If the 2 storms never merge together the Joplin tornado would of never happened.

Yeah, mergers are so important on days with weaker low level shear especially.