The April 26, 1991, Tornado Outbreak: A Case Study

[@dustin6528]

I had a VHS called “Storm Chasers” produced by A&E I think. It was narrated by Bill Kurtis and featured the Andover tornado. The footage in the beginning of this video scared the crap out of me as a kid but fascinated me at the same time. I had both a phobia and love for tornadoes going forward, though the phobia gradually transitioned into a healthy respect after learning more about weather and meteorological setups.

[@s1kkris40]

Great video as usual Trey! The violent rotation of that Andover tornado is just crazy. Not to mention the quality of videos in 1991 that show that rotation is just amazing.

[@ConvectiveChronicles]

Thank you! Yeah, there are so many incredible videos from this outbreak, many of the Andover tornado.

[@thekoolaidkid337]

HEY GUYS TREY HERE!

[@miche1df]

Hey Trey, guys here.

[@Cdunlapweather]

Hey everyone Trey here

[@maryc2562]

Love this video! Truly a learning experience!

[@boopshanaa]

Fuck yeah, Trey. Fuck yeah.

[@theslow-by5co]

Hey here, trey guys

[@miche1df]

Dude I watched that Nat Geo documentary so many times as a kid that I basically know it by heart. It's really eerie looking back at the part about a hypothetical New Orleans hurricane and realizing how closely they predicted Katrina a decade before it happened. Also it's painful hearing an event I was alive for referred to as "thirty or forty years ago".

[@edwardgutierrez2638]

Yup it’s called Cyclone!

[@intraterrestrial5035]

We're getting old 🤣

[@windwatcher11]

Thanks for cracking open the history books for us, Trey!! Great analysis. Excellent graphics, too. Really dug the shear vector/right- & left-mover explanation. Made sense as never before. Whole thing was well done!

[@ConvectiveChronicles]

Thank you very much!

[@zachsteiner]

Thanks Trey! Been doordashing all evening (rents due) and it’s really starting to be a drag. Now I have something interesting to listen to while working. Really nice change of pace, covering a classic event like this one. Can’t wait to dive in! Oh also, really like the diagrams for divergence aloft you included.

[@ConvectiveChronicles]

Thank you! I figured I’d add an actual 3D diagram for divergence/diffluence instead of doing my normal awful 2D drawings of it.

[@Scarecrowwx]

I feel like vids like this are going to be really important this year, considering this was a el niño into a neutral, which is what this year, as well as 2016 was

[@runt9]

Incredible video, Trey! So much I could talk about, but I always like to highlight the one big takeaway I learn each video, and for this one it was the vector perpendicularity diagram that really opened my eyes a bit. It's such a clear and succinct way to showcase how storm collisions are far more likely to happen with a pure 90 degree angle vs one that is slightly off-center. I also just want to continue praising the ongoing efforts to beef up the quality of the videos, with more diagrams like the one for diffluence, drawing the EML over a terrain map of the US, etc, and just having a solid script and great editing. I think the most notable feature of this outbreak to me was how far west the trough was when it was that deeply negatively tilted. It seems like we just don't really see that exact setup too much anymore. Troughs tend to be fairly positive or neutrally tilted until they cross the Rockies, lending the negative tilt more focused on the Southeast. I wonder if this plays into the theoretical "shifting" of Tornado Alley a bit more towards the southeastern US. Cause my lord was this thing negatively tilted as it was crossing the Rockies and lee cyclogenesis was underway. Definitely one of those outbreaks where every aspect can go in a textbook. The incredible pictures/videos, the 500/850mb maps, the soundings, everything. Just so picture perfect as far as the recipe in the cookbook coming together to produce a significant tornado event. Thanks again, Trey! Went ahead and hopped onto the Patreon as well. I've said it before and I'll say it again, you've provided me with dozens of hours of content and I'm glad there's an easy "set it and forget it" way to support your ongoing efforts for the channel, and I hope your Patreon pops off and succeeds for you!

[@ConvectiveChronicles]

Thank you so much for the kind words, and for subbing to the Patreon! Much appreciated! Been trying to continually do better with adding in diagrams and such to the videos. You're right; it just seems like we don't get these types of setups anymore. May 2019 seems like the last time we had consistent large, negatively tilted troughs moving through the Plains. It's definitely an interesting topic that would benefit from some research.

[@DanRoss11]

Good point about ideal shear vector orientation NOT being perfectly perpendicular to the initiating boundary. Hadn't ever considered that. Thanks for posting another one of these!

[@ConvectiveChronicles]

Thanks for watching! Yeah, I think a lot of people are under the impression that simply the more perpendicular the shear vectors are to the initiating boundary, the better, but that’s not exactly the case.

[@weeshock3480]

"Very juicy air mass ahead of the dry line..." I'll say; Wichita was so humid, hot, no wind, nor a cloud in the sky. Walked to work at 3:30pm, and had no inkling there was even going to be rain, much less a tornado. When the warning was issued, we closed shop, walked outside, and it was still sunny at Towne West, but the sky to the south was dark, ugly, and black.

[@JustinLHopkins]

I live in Wichita and I was just a little kid but I remember the sky being green. We went to look at the damage and there was nothing left. It’s unbelievable that nature on earth can produce 300+ mph. It reminds us that we’re still not in charge.

[@nightshadelenar]

Very informational! I've been watching your case studies off and on since the start of the year, and has been quite interesting having a deeper dive into new and old cases alike. Usefulness without a textbook for those who are curious.

[@ConvectiveChronicles]

Thank you so much!

[@bryantburough8419]

Trey, as always, another phenomenal breakdown of a notable severe weather event. Love the work!

[@ConvectiveChronicles]

Thank you so much!

[@krzy1867]

This new style of briefings of old setups that you’ve adopted is amazing, loving the concise analysis, great job as always Trey

[@ConvectiveChronicles]

Thank you so much!

[@JustinLHopkins]

The video of the 1991 Andover F5 was aired on stations all around the world. Video recorders were expensive still and not many people had seen such a violent tornado. I remember watching it for the first time with family and we were all speechless at the power of nature.

[@bbybby91]

YESSS 🎉 Was absolutely one of the tornadoes that got me into tornadoes, the fury on the plains VHS I believe it was.

[@CeltonHenderson]

Thanks for sharing Trey. Its difficult to state just how big of a difference the WSR-88Ds were about to make in the forecast and warning process. Unfortunate timing with this outbreak and others like Plainfield happening before the full system was up and running.

[@Coop-2168]

I was always really fond about this outbreak as a whole. Something about it was quite fascinating to me even though ive studied the biggest/most textbook outbreaks this one always takes my interest. Love the video!

[@ConvectiveChronicles]

Thank you!

[@AndreWehrle]

Awesome, Trey! 0:42 I don't believe I'd seen that video of Red Rock before; most of what I'd seen of it was either early in its life when it appeared as a truncated cone with a multivortex debris cloud beneath it, or from further away. That has to be at or close to its peak intensity and clearly shows it was at least every bit as violent as Andover. Speaking of, I hadn't seen this particular video you used of Andover until after April 27, 2011 happened, but even then I thought the Tuscaloosa tornado was a visual clone of Andover as it passed south of the ABC 33/40 skycam, and this footage, taken from the same angle relative to the tornado's track, just further confirms that. Sharply angled on the leading edge of the funnel, nearly vertical on the trailing side with huge chunks of debris being flung around it, and whirling at dizzying speed. 3:20 I think moderate risk was used then; I have seen some outlooks from for example the November 1989 tornado outbreak (F4 hit Huntsville, AL) that included a moderate risk designation before later being upgraded to high. However they didn't always have a moderate zone separating the slight and high. The category designation was probably more subjective based on the forecaster's opinion and not strictly tied to certain probability gradations like it is now. I think they continued putting out high/slight outlooks with no moderate in between at least occasionally as late as 2001-2002, but I don't recall seeing any after 2002.

[@ConvectiveChronicles]

Thank you! Yeah, the Andover tornado definitely had some similarities to Tuscaloosa, especially in the Duke Evans video at the country club. You might be right; seeing the High Risk without a Moderate buffer in between seems foreign. We’ve definitely come a long way since then.

[@travisrock1640]

Thank you so much. I'll never forget watching this from the base before and juat after it went through.

[@jamesstemmler7620]

Been so busy last couple days finally getting a chance to sit down and watch!😎

[@MesoShed]

Hey Trey, maybe there’s already a video out there, but is there a video on fronts and boundaries and how they help storms form? And different setups with fronts? Thanks to your videos I’m starting to grasp some of the concepts of severe weather, but fronts and boundaries have always confused me a little. Thanks Trey! I can’t believe I’m learning all you have to teach for free!

[@ConvectiveChronicles]

I always plan on keeping the videos free; I just want to share my knowledge with fellow weather lovers! I don’t have anything specific yet on fronts/boundaries, although I did touch on them in my Weather Map Analysis series (see Playlists tab). I’ll add a fronts/boundaries video to my list!

[@fireman305]

This outbreak and the Hesston outbreak of 1990 sparked my interest in tornadoes and severe weather.

[@brenda_clark]

I always learn something new from your videos. I found the diagram of the angle between the shear vector and the boundary very useful. I liked how it shows whether the right and left movers will be able to maintain a discrete mode. Thank you!

[@ConvectiveChronicles]

Really happy to hear that; thank you!

[@ethanverbeek1226]

Im a little late to this video but I am glad it ended up in my For You Page. I love how much depth you went into the environment and you taught me a lot of things that will have me more knowledgeable for when events like these occur again. Great video earned my like and subscribe

[@ConvectiveChronicles]

Thank you so much! I’m glad you enjoyed it

[@80sNewWaveGeek]

These videos are always fascinating to watch, thank you. I didn't realize until I began viewing your channel that some of our worst tornadoes were spawned after supercells would merge together.....

[@ConvectiveChronicles]

There’s some really cool new research being done on storm interactions/mergers that will change the game for chasers…will have a video out this spring on that.

[@trex0021]

Loving the in-depth meteorological discussion with these case studies. One I'd like to see covered is the 1996 Oakfield Wisconsin F5.

[@ConvectiveChronicles]

Thank you! Will add it to the list

[@michaelonesty]

“Hey everybody, Trey here. Today, we’re going to dive into the meteorology behind the gust of wind that ruined my par 4 yesterday”

[@AlwaysChasingStorms]

Is it weird I'd actually listen to that?

[@joshntn37111]

Damn I enjoy this channel so much!!! Thank you!!

[@ConvectiveChronicles]

Thank you so much!

[@edwardgutierrez2638]

Right there with you Trey on my interest in weather and meteorology with that VHS Nat Geo Cyclone video. I’m sure that VHS video is laying around somewhere back at my parents house. Peter Coyote did such a great job narrating it all. I actually got to meet Howie back when I was at Texas Tech for an AMS conference. Real down to earth and intelligent guy.

[@ConvectiveChronicles]

Peter Coyote did an amazing job narrating that video. Such a classic! Howie is a really cool dude; very fortunate I got the chance to work for him during my time at OU.

[@MightyMuffins]

Catching up on all these from my overnight shifts. Ah this outbreak was nuts. It's almost hard to kick the Andover tornado out of one of the top 5 craziest tornadoes you'll see in terms of the shear visibility and the motion that had on it. The Duke Evans video still lives rent free in the METR community I think still in terms of the quality for the time and just....you can hear it from that distance. It's nuts. What I think is interesting is the outflow boundary having some affect on this. I kind of forgot about that in some of the research that was done on this event. I will say the soundings including that insane 00z Topeka are wild. That moist layer and still a solid stout dry layer that had was something really remarkable. Such a shame there was no closer radar data or High res stuff you get these day or even like the El Reno or Moore tornadoes. Still, the ground truth more than shows, you don't need the radar to show how insane this would have looked. Oh and I never seen that red rock tornado video there near the end....that was sick. Actually the Windfield one is bonkers.....that looks like it was taken on a small hill...which is impressive in Kansas. Crazy how many wedge tornadoes this produced overall.

[@EvilApple567]

I hope you don't shy away from similar events in the future, because your ability to make inferences (or even just theorize) certain aspects of them due to deeper scientific foundational understanding makes these more unique compared to other breakdowns. I'd even say there's a good niche for these types of significant, yet incomplete data events that most others simply can't dissect, even theoretically.

[@ConvectiveChronicles]

Thank you! I definitely won't be shying away from these older events; I enjoy trying to fit the puzzle pieces together of these events that were pretty foundational in our understanding of tornadic storms.

[@kayeas716]

I guess it would be somewhat obvious, but I never realized that “perfectly” perpendicular shear vectors could actually end up messy, actually really cool that you talked about that. great breakdown as always!!!

[@ConvectiveChronicles]

Thank you!! Yeah, intuitively, you'd think a purely perpendicular angle would be best, but that's just not the case.

[@hunterwolff-schollmeyer3902]

There were some absolute monsters this day. What an incredible weather event, definitely a benchmark for the Great Plains.

[@13lbaseball]

Absolutely love these videos! I'd love to hear about the June 17th, 2010, Minnesota/North Dakota outbreak.

[@ConvectiveChronicles]

Thank you; it's on the list!

[@roadkillavenger1325]

The high pressure area off of the east coast at 13:23 had something to do with the storms over Oklahoma and Kansas?

[@ConvectiveChronicles]

No, I was simply drawing the wind profile in place the Plains over there

[@JustinLHopkins]

This is excellent. I live in Wichita and I was just a little kid but I remember the sky being green. We went to look at the damage and there was nothing left. It’s unbelievable that nature on earth can produce 300+ mph. It reminds us that we’re still not in charge.

[@ConvectiveChronicles]

Thank you! You're absolutely right; Mother Nature always has the upper hand...

[@SuperCellChasing]

Awesome Video man Your awesome!! Thanks for these.. Honestly i learn more from these videos than anything else in KZbin very well done..

[@ConvectiveChronicles]

Thank you so much!

[@SuperCellChasing]

@@ConvectiveChronicles For Sure Bro!! 2024 Tornado forecast Coming soon?

[@ConvectiveChronicles]

@@SuperCellChasingYes...aiming for late February

[@raymondguilbeault4585]

Ahh yes that infamous overpass event that spurred the myth of sheltering under overpasses was a good idea. Well that was busted 8 years later during May 3rd 1999

[@joseph-frankbrocchus6575]

I remember that day / I don’t remember a squall line or derecho / didn’t even rain in Tulsa / if I remember correctly, this was a kind of day, where there were not going to be as many storms? Great video and as always, Thanks for keeping us safe and informed

[@ConvectiveChronicles]

Thank you! Yes, the coverage of storms was not expected to be incredibly widespread, as the signs pointed to an overwhelmingly discrete mode. But any storms that did develop were expected to be pretty nasty.

[@christian4688]

2002 La Plata Maryland F4 would make an interesting study... a violent tornado that stayed on the ground for 70 miles is pretty much unprecedented on the eastern seaboard.

[@Stollnews]

really really interesting, thanks a lot for this case study and all the graphics!

[@ConvectiveChronicles]

Thank you!!

[@jawmedia7575]

Excellent work my guy. You're awesome 👌

[@ConvectiveChronicles]

Thank you so much!

[@GophCrsn622]

Great video Trey!

[@ConvectiveChronicles]

Thank you!

[@lordlobster3793]

Any chance you could go through events that spawned large tornadoes such as Hallam 2004?

[@ConvectiveChronicles]

It’s on the list!

[@VCBee042]

hey you pronounced beatrice correctly! i completely forgot about the washington to beatrice tornado because andover stole the show. i was 8 years old at the time and it was my first tornado warning that i remember. my little brain was fascinated with tornadoes from that day on.

[@paulreed1407]

Trey still waiting on some more Wisconsin and Minnesota tornado events case studies I feel they don’t get enough Mentions really interesting

[@variant1]

I know you said it’s tough to do the older events, but it would be awesome to see a video done on the June 8, 1995 TX panhandle outbreak

[@ConvectiveChronicles]

That one might be easier to do since it was during the VORTEX project, so it has a good number of journal articles written about it

[@Meathead72]

Great video! I’d really like to see a case study on the April 12, 2020 Easter tornado outbreak.

[@ConvectiveChronicles]

Thank you! It’s on my list!

[@64BBernard]

I see you're using Gempak for some of your surface plots, Trey. Since I switched to AWIPS, I don't use Gempak as much - but it is very handy for older case studies.

[@nazcarcup]

Great video as always

[@ConvectiveChronicles]

Thank you!

[@derekb7814]

Outstanding presentation!

[@ConvectiveChronicles]

Thank you!

[@sabishiihito]

April 1991...man I was coming to the end of 7th grade. That footage of the Andover F5 is (in)famous! When that EF3 twister hit Andover a few years ago, and some initial damage photos made it look *really* bad, I was thinking "Here we go again."

[@stormwx]

An idea for like a short video will be the Ciudad Acuña EF3/4 in 2015. Pretty deadly tornado for only a mile of track. (14 fatalities) Also some pretty intense damage was caused by it to well built brick homes.

[@bigtodd]

Love the use of diagrams. Really helpful

[@ConvectiveChronicles]

Thanks; I’m trying to be better with that from here on out.

[@paulmarruffo4037]

Any chance you could do a case study on the 2015 Rochelle, IL tornado and mini-outbreak? One of the most photogenic tornadoes of all time, and since there's still debate about it being an EF-5

[@ConvectiveChronicles]

It’s on my list!

[@__Dave__]

1:1 like-to-view ratio, let’s keep it up!

[@makhatchet5894]

Hell yeah I watched the crap out of that VHS too! I had a few storm chaser tapes from the 90's too. I think someone posted them on YT.

[@girth_brooks]

I'm not sure if you'll see this comment, but my family was hit by the Winfield KS tornado from this day, almost left no trace of their home. A young lady down the road also died in it. I have tons of pictures and even a short news interview they did on scene with my Grandpa showing the damage they received.

[@ConvectiveChronicles]

Wow, that’s crazy…thank you for sharing that.

[@EverydayLJnz]

Yes. The king is back!

[@Michael-gi5th]

Thoughts on this season Trey?

[@ConvectiveChronicles]

Planning on releasing a video on that in late Feb.

[@intraterrestrial5035]

Your vids are fantastic... Prolly a low chance of it happening, but if the data allows, a breakdown of June 3 1980 would be wild, Grand Island NE & nearby got hit by 7 tornadoes that night

[@ConvectiveChronicles]

Thank you! That event is definitely on my list; there are a few journal articles on that event, so it might be a bit easier to do.

[@tctorguy]

is there any way to make formal requests for case study videos? I would love to see a case study of the 1-22-17 tornado outbreak!

[@ConvectiveChronicles]

That one’s on my list!

[@treywfsmith]

Great video!

[@ConvectiveChronicles]

Thank you!

[@ignorantleftwingusa]

I was 12 when the Skiatook, Ok F4 hit my neighborhood 1991

[@DJ-iu5bb]

I used to live in Wichita Kansas and im pretty sure in 92 I was born in 91 I knew what Danger was cause it sparked this fear I must of been screaming as a 2 year old I still cant find data on it on Wiki

[@r.nicogorodetzky3084]

HE'S BACK :)

[@araydog]

The first modern day tornado outbreak. The first one that was well covered.

[@adamwigginss]

I would love to see a breakdown of April 8th 1998

[@DanielSimon-b2o]

Can you cover the Hurricane Ivan tornado outbreak? I think that would be something really cool and different!

[@ConvectiveChronicles]

I’ll add it to the list!

[@EerierFish17]

Can you do the 1989 Bangladesh tornado (the deadliest tornado ever)

[@ConvectiveChronicles]

It'll be pretty tough to obtain data from that part of the world that far back, but I can try.

[@meghanhause9435]

@@ConvectiveChronicles I agree with that, plus Bangladesh doesn't have amount of data recording as we do in the US.

[@EerierFish17]

@@meghanhause9435 that doesn’t mean it’s impossible

[@myria9644]

Some of the first internet footage I ever saw, that overpass video I feel did some harm however

[@nazcarcup]

I'd love to see the March 28th 1984 SC/NC outbreak covered.

[@ConvectiveChronicles]

Interesting, I’m not aware of that event…I’ll do some research and add it to the list.

[@nazcarcup]

@@ConvectiveChronicles big thanks Trey

[@asap314]

TEXTBOOK 🗣️‼️🔥🔥🔥🔥

[@Missygail78]

I was in a tornado from this day. I was at zinc ranch in oklahoma, it was the girl scouts ranch.

[@ConvectiveChronicles]

Glad you made it out ok

[@Snowstar837]

This really strikes home iust how spoiled we are today with the resources we have available for both forecasting and analysis!

[@ConvectiveChronicles]

Totally agree!

[@ac7666]

The first clip looks crazy

[@GreatGray8790]

Thank you!

[@tornadotrx]

Yeah okay "Trey," we all know you're writing your videos with TreyBot's expert analysis..

[@adrianlong8267]

Hey what about the 1953 tornado of Waco? May 11 1953

[@ConvectiveChronicles]

The farther back you go, the tougher it gets to find good data. But it’s on the list

[@fts_space_shark]

YAAAAAAAS CASE STUDYYYY

[@1LightningRod]

Another fantastic video Trey! I saw my first tornado on this day, west of Topeka. Here's my retrospective on the event I put together a couple of years ago, and features more visible satellite imagery: kzbin.info/www/bejne/fmfSqYWLmKaDatEsi=mn6OEYYYsmbmFRd0 I have a couple of large binders of printed material from the event. It includes upper air charts, hourly weather roundups, watches and warnings, etc. Again, masterful work.

[@ConvectiveChronicles]

Thank you so much, Rodney! Excellent retrospective; what an event in which see your first tornado, a pretty beefy tornado at that!

[@1LightningRod]

@@ConvectiveChronicles Indeed, can't complain about what we saw. However, would love to have chased this event with today's technology.

[@tornadofire82]

Do the May 31 1985 outbreak.

[@SIGINT007]

Quote unquote "shelter".....bwahahahahaha! Funny, but very true. Terrible idea.

[@calebcopeland3436]

GREAT VIDEO ❤?!?!

[@ConvectiveChronicles]

Thank you!

[@vansavant822]

Based af...

[@ericascali5427]

😢😢😢😢😮😮😮😮😮😮

[@tommywoods2548]

Oh hey look destruction on my birthday! (Day not year)