The May 20, 2019, High Risk: What Went Wrong? 

Another great video Trey; it's great that you're breaking down these 'underperforming' events as well as those that produced significant tornadoes and outbreaks, its really interesting to hear the factors that can make or break these set ups; it's a really valuable learning opportunity, thank you!

Just shows weather is unpredictable

Great subject. Learning why an event that was so well primed did NOT fire off actually proved more interesting to me than an event that should have fired off and actually did. This was 45 of the best minutes I've spent on RU-vid. Thank you for sharing your observations and expertise!

Another edifying deep dive. Thank you for taking the time to make these breakdowns. A unique channel in the weather niche.

You’ve talked about long track tornadoes on the channel before, but can we talk about large tornado setups such as the Pachuta-Soso tornado on 12 April 2020 or the Greensburg, Kansas tornado? Great work as always

Thanks for this. I live in that area, and we were very concerned that day. That morning was overcast and hazy, and it stayed that way most of the day. It was forecast to be fairly warm but never made it. I always thought that saved us. If we had reached forecast highs, it is conceivable that the cap would have been broken, and things would have been very different. Love your channel and always look forward to these analyses.

Loved the overall breakdown of this event Trey! Just subbed to your page, keep up the good work!

While watching skewT videos, this one came up as recommendation and had to watch it first. It was my very first tornado chase day, honestly I was overwhelmed by the "high risk" because I knew the danger for beginners. Also, every single person from the area I met was very concerned. Like you mentioned in the video, I was glad that the threat didn't happen. By the way, I missed the Mangum tornado by 15 minutes due to the traffic on SR34 😅 Thank you for your time and efforts on the study!

Fantastic video Trey! I never fail to learn something from your videos!

I distinctly remember watching coverage of this as it happened and seeing weather channel people reporting temps in the 50s in that sweet spot. Pretty much everything they had to show was just showers by that point, everything tornadic had already been squeezed out. Sweet video, these are addicting.

Driving out from Eastern NC to Guthrie OK to chase this event, it was a bit of a disappointment after taking turns driving straight through. The rest of the week was decent chasing at least. You've got some of the best videos on YT. I really like your breakdown of these underperforming events too, thanks for the uploads.

Thanks Trey for your work compiling this information succinctly! I will refute one of your claims though-the low level lapse rates at Norman were actually fantastic as seen in the sounding at 38:30 in the video. The 5.3 °C/km 0-3 km lapse rate average value included the sharp inversion right at 3 km or roughly 675 mb, skewing that number; whereas in the BMX sounding, the inversion was present just above 3 km, allowing the 0-3 km avg. lapse rate to read 8.8 °C/km while the MLLR suffered. I imagine the OUN 0Z LLLR up to the inversion was actually closer to 6.5-7 °C/km just eyeballing it compared to the 3-6 km's 7.8°C/km. Thus, it could be concluded that the lack of noteworthy forcing in the OWS was the true observable failure mode as it could not overcome the EML present. Reading the lapse rates as not averaged across their specific range will result in generalizations like this, when in fact the given OUN observations' lapse rates were supportive of storm development and maturation outside of the inversion layer!

Absolutely a phenomenal case study! You channel was recommended to me, and it was really good!!! Keep it with the great work

such an interesting and dynamic storm system! GREAT video!!

I would like to say thank you for these case study videos and the great detail you go into. As a 30 year weather enthusiest I have learned a tremendous amount of new to me information on tornadic set ups from you. I am in n.w. alabama and in my 50 years there has been 3 f-5's, 2 f-4's, and at least 5 f-3's whithin 50 miles of my home. I watch all storm system carefully.

I KNEW you would make a video on this, thank you!

Great job as always!! Very informative! Thank you

Extremely informative as always cheers bud

As an amateur chaser, thank you for all the comparisons that you do. It's really nice to get details on this stuff.

I distinctly remember the mass chaser convergence going for the Mangum, OK tornado. Once I saw that, I elected to just West onto the dry line and was basically bunny hopping between tornado warned supercells. Picked up a rain wrapped wedge near Guthrie, TX that came out of the rain for about 40secs. The main reason for jumping West to get out of the chaser mess but also to try and get on the storms when they were clean and not too HP yet, with better heat being fed in behind them along that dry line

I think the Citizens of Moore, Oklahoma had the biggest sigh of relief for obvious reasons

Love your stuff dude. I’d love to see a recap on the December 21, 1971 Mississippi Delta tornado outbreak. 12 tornadoes including 8 of those being F2+, 2 of them being long tracked F4’s in Mississippi and the only official F5 in Louisiana’s history.

It doesn't seem so much a bust, but a placement farther west and somewhat shorter lived events. I do think storm development tends to favor the north or northwest edge of the EML and there just wasn't enough of an eastward push with that weak shortwave to nudge the EML and corresponding favorable zone more south and east. The synoptic front was quite stationary and it was mainly outflow that eventually drove the line east with the better shortwave energy frontal forcing still lagging behind.

May 2019. That whole month was pretty insane. It seemed like these intense storm systems were getting thrown at us every other day. One of the TV meteorologists explained why this was happening. It something about the amplitude of the jet stream. The ridge was near Washington state and the trough was near Arizona with Oklahoma basically being in the line of fire. There was a lot of flooding as well. Keystone Lake was filling up a fast. They had to open the dam to let water out and as a result, flooded some communities downstream. Didn't help that the levees weren't in good condition.

I remember this day and week! I live in East Oklahoma and the night of this day we got multiple tornado warnings in our area. Still i was surprised there wasnt a long track violent tornado that week.

Hey Trey, great to see some info on this event, I hear/see it referenced every time someone on Twitter thinks something is gonna be a "bust", you just see "Oh looks like another May 20th to me!" When you really dug in and showed that it took an army to stop what looked to be a freight train of a violent tornado outbreak. I had a couple notes from what I picked out from the video, but in general it's crazy just to see something as insane as a 45% hatched tornado threat, and some of those parameter spaces were off the charts. I think that 12z Midland observed sounding you showed early on needs to be in a museum. You've showed some textbook "loaded gun" soundings before but my lord that is picture perfect. 3k MLCAPE, 360 eff SRH, moist layer up to 800mb, big thick EML with strong lapse rates, all at about 7am. That screams "a severe weather outbreak is imminent as soon as this cap busts". Kinda the same deal with the 21z Norman sounding. Every bit you look at is just shouting "tornado outbreak"... except the lapse rates are just a bit unimpressive. Jumping to 0z, I'm sure the people of Oklahoma are thanking their lucky stars for the cap because 3500 MLCAPE, over 500 SRH, on top of 163 3CAPE is so incredibly frightening, just seriously thank goodness there wasn't a discrete supercell in that environment. I also noticed in a couple of the soundings it looks like a bit of vertical mixing was worming its way in. Nothing too serious, but especially compared to the models there were some inverted-V profiles with some temps I think I saw up into the mid 80s. It likely doesn't matter that much with dew points as high as they were, but I wonder if some of those small breaks in the clouds help some of that drier air from the advecting EML work down to the surface a bit and stunt some of the moist updrafts from happening. The biggest thing I want to point out is how perfect this video showed why you should NOT rely on composite parameters. The 23z RAP sounding from KFSI had an STP of 11.3 and a Supercell param of over 37. Those are so far off the charts the SARS had a hard time finding analogues, only 2 supercell matches found because of HOW HIGH the parameter was. If you simply look at the composite parameters, you're ringing every alarm bell and screaming danger at anyone who would listen. Then you look at the SkewT lines more closely, see a slight bit of vertical mixing, a bit of capping, a very stout layer of VERY dry air above 750mb, and unimpressive low-level lapse rates and it becomes clear that any updraft that fires in this environment is going to get immediately choked off. It's such a perfect showcase that no matter how many pieces of information you try to roll into a single number, you 100% of the time MUST look at the whole picture. Even just the sounding as a whole doesn't tell you that there's an ongoing MCS supported by weak forcing from a slow-moving trough that is gonna have a hard time busting the cap. There's too many things to ever rely on "big STP = big tornadoes" and I love how perfect this case is to support that. Anyways, fantastic video Trey, thanks again, and I can't wait for more case studies as we slowly transition out of the big chasing season into summer, though who knows with the overperforming El Nino transition this year haha

I believe we were under the Mangum storm when it was clashing with the cold air. Vividly recall us having the windows down and suddenly a new rotation went over us and I felt both warm/humid and cold/dry air at the same time. My hair got stuck upwards for a little bit from that.

I don't think you need me to say it, but good job again! Another very interesting aspect to this event was the tornadoes in SE KS/SW MO well north of the warm front. Iirc temperatures were in the 50s and those storms were elevated but produced a few small tornadoes. The first of three straight days of tornadoes in the SGF area.

You should do a video about a Wisconsin tornado outbreak. There’s been a few large ones that may be interesting to look like

Great vid, would love to see one like this on the March 17, 2021 high risk in Dixie.

Great video! Loving these breakdowns. Do you have any plans do a video on the May 24th, 2021 Selden, Kansas Supercell/Tornado? It was a very interesting day and storm.

Your analysis is pretty on par with Tropical Tidbits (Dr. Cowan) except severe wx vs. tropical obviously. These videos are fantastic and you should be proud of what you do. I always look forward to them :)

Yeahhhh I remember that. The Dallas/Fort Worth area was supposed to get hit and all we got was dark scary clouds....and rain. I was so worried that I hide in some building and nothing serious happened.

Very informative!

Another very good video that provided a lot of information / This was good that this did not happen as Oklahoma was already experiencing catastrophic flooding during the months of April, May and June

Great Video!

It's important that we can learn from this "failed outbreak". Knowing which elements trigger a tornadic supercell and which elements cause a non tornadic thunderstorm or only small showers is essential in the understanding of tornados.

Remember this day well from all the Twitter weather 'experts' coming out of the woodwork. It's amazing how accurate you can be in meteorology with hindsight on your side! 😂 Great video as always!

good stuff. i do remember that May being a crazy month.

Great video! Two true high risk busts that might also be interesting are 4/11/2005 or 4/13/2007. Also, could you add either the 7/29/21 or Hurricane Ida tornado outbreak? 2021 was a historically active year in the Philadelphia region and one of the Ida tornadoes touched down very close to me.

Who's here after yesterday's high risk forecast in Oklahoma? I'm not a weather expert, but it feels pretty similar given how the high risk forecast/models thankfully "underperformed" yesterday (May 6, 2024).

thanks trey! these vids help me learn this stuff since i cant go to school for this stuff but i dont need a degree to storm chase :))

I think when people say “bust” most refer to the intensity of the event. There were definitely numerous tornadoes, some strong. However it clearly did not live up to the expectation.

The night time tornado out by Locust Grove, OK looked pretty significant on radar. EDIT: I did a bit of research just now. It ended up being an EF2. the actual town it hit was Peggs,OK at around 9:30 PM local time

I think that's what everyone means by bust, it was a bust for what was forecast, that's what everyone usually means by bust Great video BTW, very lucky it didn't turn out the way they thought

April 5 2017 might be a good one to look back at.

Awesome video. 👍🙂

Crazy Oklahoma was supposed to be gone with the wind that day yet that didn’t happen

People, just remember that the National Weather Service predicts weather, they don't create weather

This lower-end outbreak (which definitely did not live up to what the CAMs such as the HRRR were forecasting) was part of a bigger May 2019 Tornado Outbreak Sequence.

Great video :)

5/20/19 was not a bust, but rather a severe underperformance from what was expected

What went wrong: The weather realized my general area was part of the risk bubble, and so, as is tradition, elected to crap out into a squall line that even found a way to be uneventful by squall line standards when it got to me.

People using bust 🤦🤦😞. Really all that is - they are disappointed wanting their adrenaline "fix" for seeing violent storms. In recent years SPC hasn't taken anything for granted (4-8 day convective outlooks) and if they saw something that's a red flag, even in a "slight" risk (2 people killed in that last week btw) there really isn't any such thing!

also the fact that we were potentially facing the april 27 of the great plains, there is potential we could have had another EF5 EXACTLY six years later. same hurricane naming list as well

Great video Trey 💯, I agree that this wasn't a bust it just unperformed but there's a large number in the weather community that doesn't understand the difference between a bust and a unperfomce in a Outlook, i read something that said a high risk can verify with a tornado of at least ef2 rating or higher so yeah and I think of a bust as there being on 0 -5 tornados in a outbreak forecasted to have several strong to possibly violent Tornados and I don't see it as a bust if there was a few EF2 to EF3 tornados but anyways if this had played out it could've been the top 3 tornado outbreak of the southern plains

I believe if this event did live up to expectations, it would've been the worst outbreak since 4/27/2011

i wish radars would do a better job at getting rid of all the clutter.

Their were other contributiong factors that might have caused the reason in the eml to get stronger during the day. Elevation, drought, and wildfires not from mexico but new mexico. Usually when it comes to smoke the smoke rises and still holds its warm dry air in that spot where a normal eml would occur near the surface during a drought which likely these key factors were the cause of the eml to increase. So that drought in the southwest was likely a big cause of the eml to unexpectedly increase with that warm dry stable air being lifted from both the smoke and the drought areas

What’s your opinion on next weeks setup?

The day 5 outlook from this event is almost identical to the one we’re seeing for the 15th of April..

One thing I think there needs to be more research on is wildfires and smoke and if it can limit overall outbreaks or just storm genesis in general. I know something like that would be really tricky cause like in a case like this it may it may have been one of the limiting factors but it would be interesting if someone found cases where wildfire smoke generally played a major issue either in overall capping a large case storm outbreak or in fact it didn't do squat due to other factors overcoming it and there we other issues. hehe I don't even know how one would even going about starting that research project other than going through SPC data and wildfire data/Satellite data and seeing what happened.

EML giveth, EML taketh away.

If there’s a cap, why does the hazard type still show as a PDS tor?

🔥

I was right in the middle of the high risk thank god this what could have been a catastrophic event didn’t happen.

I've a feeling that if the reality of May 20, 2019 had matched with the forecast for that day, then there could have been a "May 20, 2019 Super Outbreak"! I personally define a super outbreak as any tornado outbreak that involves more than one F/EF5 tornado. After all, both the April 3-4, 1974 Super Outbreak and the April 25-28, 2011 Super Outbreak involved more than one F/EF5 tornado. Indeed, during the peak of that outbreak on April 27, 2011, the radar map of Mississippi and Alabama (the two hardest-hit states) looked remarkably like the HRRR's forecast radar map for May 20, 2019 in Oklahoma: a march of the supercells. You DON'T want to see a march of the supercells; because a march of the supercells, with its swarm of discrete supercells, is pretty much always a prolific tornado-maker! You could even call a march of the supercells a TORNADO FACTORY!

I think these kinds of videos, an interesting topic could be the January 22, 2017 event.

My question is, if things played out the way they were forecasted, would Moore likely go through the same déjà vu that I went through six years prior.

next= what went wrong with the april 4 2017 severe weather event for georgia

The conga line that day...

Was there…the only thing wrong was the massive chaser convergence and multiple chaser v. chaser vehicle crashes

I have family that live down in Okeechobee, Florida that prepare every tropical season as if they are going to have not 1, but several. My uncle always tells me that spending a little bit more in anticipation of a major, multi million- billion $ storm is better than taking a chance on doing nothing and end up frantically trying to board up windows, trying to lay down sand bags, and trying to avoid losing the lives of loved ones. And same goes for severe weather. When the SPC puts out a 4-8 day outlook showing a 15%/30% for specific areas. Regardless if it ends up becoming a line of storms, or there is an eruption of multiple rotating updrafts that produce long track, violent tornadoes. For some reason we have a demographic of people who think that mocking anything that is a part of math and science somehow gives them gratification of some kind. I will say this though. I'd rather have a bust from the Storm Prediction Center outta Norman, Oklahoma, from credible people, doing hard thought out analysis, and putting in that input into models that have for the most part been over 90% affective. Than to keep telling people something is going to happen with zero evidence, zero calculations, zero anything! Just a boat load of irrational beliefs and nonsensical data that don't amount to anything, and it fails over and over, with their predictions having a huge goose egg. I believe there is a new type of weather prediction model that has the capability of accurately predicting when and where a supercell storm will occur and whether or not it will produce a tornado. If I'm wrong about this please let me know. Because I am just going off something I think I remember hearing. Someone had explained this to me and said that it was creepy and very amazing to see some of the runs that they used, which were of past tornado outbreaks, of storms that developed almost identical to the real storms that had destroyed towns and ended lives and homes. But it hasn't developed consistently when predictions are needed. I know I'm probably off a bit on this. So I hope someone has more info on what I'm trying to explain lol. Anyway, thanks to all of the folks at SPC, and all the NWS offices around the country, and at out neighbors in Canada, the UK, Mexico, Australia, and the rest of the world.

This was honestly the last day I decided to chase. Saved up took off work and did nothing but waste gas lol haven't really seriously chased since :/ maybe this year I'll try again.

Forecasting has gotten worse over the past decade