The Great Midwest Derecho of August 10, 2020: A Case Study
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- Опубликовано: 31 май 2024
- In-depth discussion of the costliest severe thunderstorm event in US history: the great Midwest derecho of August 10, 2020. After a crash course on derechos, we'll take a deep dive into the meteorology and progression of the event and why this derecho was exceptionally long-lasting and powerful.
Thumbnail images from Daniel Acker, Lisa Schmitz (NWS Des Moines), and NWS Chicago.
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Chapters:
0:00 Introduction
1:52 Crash course on derechos
22:02 Meteorological overview begins
34:27 Initial storm organization, hail production
39:03 Bow echo catches cold front
43:49 Rear-inflow jet
47:45 DCAPE progression
52:02 Discussion of the derecho's longevity
56:09 Comparison to typical derecho parameter spaces
59:07 Satellite imagery discussion
1:02:04 Progressive or serial derecho?
1:02:29 Closing
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Resources:
NWS Des Moines event page: www.weather.gov/dmx/2020derecho
NWS Chicago event page: www.weather.gov/lot/2020aug10
NWS interactive story map on the event: storymaps.arcgis.com/stories/...
SPC page on derechos: www.spc.noaa.gov/misc/AbtDere...
"Derechos: Widespread Convectively Induced Windstorms" - Johns and Hirt (1987): journals.ametsoc.org/view/jou...
"Analysis of a Progressive Derecho Climatology and Associated
Formation Environments" - Guastini and Bosart (2016): journals.ametsoc.org/view/jou...
"Interpreting the Climatology of Derechos" - Coniglio and Stensrud (2004): journals.ametsoc.org/view/jou...
"A Synoptic Climatology of Northwest-Flow Severe Weather Outbreaks. Part II: Meteorological Parameters and Synoptic Patterns" - Johns (1984): www.spc.noaa.gov/publications...
"A Synoptic Climatology of Derecho Producing Mesoscale Convective Systems in the North-Central Plains" - Bentley et al. (2000): huskiecommons.lib.niu.edu/cgi...
"Examination of Derecho Environments Using Proximity Soundings" - Evans and Doswell (2001): journals.ametsoc.org/view/jou...
"Satellite-Based Characterization of Convection and Impacts from the Catastrophic 10 August 2020 Midwest U.S. Derecho" - Bell et al. (2022): journals.ametsoc.org/view/jou...
Definitive Guide to Skew-Ts and Hodographs: • Definitive Guide to Sk... 
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Would love a thunderstorm type video with radar presentation: HP, LP, Classic, low topped, bookend vortex. Could even cover non tornadic thunderstorms as well. Also some notable tornadoes from each variety too
Your videos are a wealth of knowledge. On July 4th 1977 a derecho hit my home town in northern WI. The winds were estimated at 135 mph at times & destroyed a large stand of 200 year old white pine virgin timber. The trees were so large that my parents said they needed to turn on their car headlights when driving through that forest. Dr Fujita did an aerial survey of the damage. After comparing the worst damage area's with the radar, he discovered the bow echo shape of these extreme thunderstorms. Thought that was an interesting fact of weather history that happened in my back yard. Thanks for these great videos!
Thank you! Wow, despite the damage it caused, pretty cool to have a piece of weather history happen in your home town.
Have you ever considered doing a case study on the December 2021 Midwest Derecho? I think it would make for a great case study given how unique it was because of not only the significant damaging winds, but the amount of tornadoes it produced with it.
It certainly was a unique event; it’s on my list!
Man this one is absolutely crazy. I've lived in Texas my whole life so seeing strong squall lines is common, but even then I had no idea just how powerful they could get. 140+mph straight-line winds is mind-boggling, I've never heard of anything more than like 80-90mph. I'll definitely be digging in to learn more about this one.
As per usual, thanks so much for the awesome case study, can't wait for more!
Thank you! Yeah, most MCS events are only capable of producing winds in the 60-90 mph range; with its 140 mph gusts, this event was definitely upper echelon and a fairly rare occurrence.
The May 12, 2022 Midwest Derecho/Haboob is another interesting one. It was well forecasted, had one of the highest end PDS severe thunderstorm watches, and had the most significant wind gust reports outside of a hurricane
Derechos are my favorite type of weather event to study, so an hour long analysis on one is just fantastic. And the information and data provided here is just outstanding. I do hope one day the Southern Great Lakes Derecho of 1998 gets covered as I consider that derecho to be the most intense in US history.
Either way, I'm still glad a derecho is getting some spotlight, I feel these kinds of storms aren't given the attention they deserve/require.
Thanks so much! Derechos are very interesting events. The derecho case studies are a little bit more difficult to fill, as they're not quite as complex and varied in their characteristics/behaviors as tornadoes/tornadic supercells, but there is a lack of material on derechos out there, and I do have some more derecho case studies on my list to eventually complete, including the 1998 one.
Also the outbreak in the Northeast on the 31 is sort of the benchmark for events of my generation. A high risk as well. Wasn't a derecho but started as discrete tornadic cells and then formed several bow echoes as they moved into New England. Interesting that there's a little uptick in severe events around Memorial Day in the Northeast too.
@@noopbloop5051 The earlier part of that outbreak, including an F3 tornado was actually caused by the remnants of the derecho, re-intensifying into discrete supercells. (Several other supercells and MCSs also formed in the northeast and the Ohio Valley) Was also the only time, so far, the northeast has even been given the high risk.
The May 30-31 severe outbreak was just one of the most violent outbreaks in general.
It went from a historic and violent tornado outbreak in South Dakota, to one of, if not the most violent derecho in US history, back into yet another historic tornado outbreak in the northeast.
AWESOME, Trey! Always looking forward to your "Case Studies". Serious amount of info. I always watch it several times so this tired mind can digest the wealth of education you share with us. It is always greatly appreciated!!
Thanks so much, Tal!
I was in west Des Moines for this, and it was INSANE to experience. It went from a bright gray outside to being so dark. Luckily the hail that came with this skirted my office! But I have friends in Cedar Rapids who are still seeing clean up efforts from this. It was an insane day!
Urbandale here. I was playing around with my younger brother, when I got a call; "Get inside, hell is about to let loose" at T-20 mins. T-15 mins later, the sirens start. And they don't stop until the sky turns black.
I was walking off of 18 green at Emeis GC in Davenport with my best buddy when the sirens went off for this bad boy. I being a severe weather junkie, had no idea this was in progress until I checked Radarscope and about fell over. I was on the I-74 Bridge crossing the Mississippi when it arrived and what a sight that was to see.
This was interesting to experience near Omaha. Clouds came in pitch black from the north, then some pretty strong gusts followed by a heavy mist. Skies cleared out like nothing happened
This storm put us out of power for 7 days, and is one of the reasons my children are still terrified of strong winds. Thanks for covering it.
Dang, glad y’all made it through alright otherwise.
@@ConvectiveChronicles we are west of cedar rapids, right about where the derecho actually started. It took weeks of clean up and a new roof, but we did make it. Thanks for the reply
Beautiful job as always. You continue to heighten the bar with these, Trey!
Thank you so much!
@@ConvectiveChronicles he's not kidding! Was listening to this while driving & it felt like I was listening to a college lecture
38:19 That point the storms gust front took an absolutely massive branch possibly 8 ft long branch and snapped from the tree right in front of my porch.
It was fricking massive. It missed the house and the porch. But brought the branch down in the front yard.
That was the only damage report out of Dodge County that day. It came straight out of Fremont Nebraska
Derechos are every bit as interesting as supercell thunderstorms.
I learn something new in every video. Thanks for explaining DCAPE and how to calculate it. I also wasn't aware of how rear inflow jets develop and I didn't know it was critical for derecho formation. Thanks for the knowledge, as always!
My pleasure; thank you!
An hour long video of Trey geeking out about severe weather? YES please and thank you!!!
Made it home 7 minutes before this hit Marshalltown for my lunch break (due west of Cedar Rapids on Hwy 30). We didn’t have near the wind speeds but 2 years prior we were directly hit by an EF3 in the 2018 tornado outbreak (same system that hit Vermeer in Pella).
Most of our damage was trees that had made it through the tornado (on the north side of town) but the derecho was the last straw.
Dang, glad you made it out ok from both of those events.
0 views, 0minutes ago. I'll update as I watch
187 views 34 mins ago
@@brendonhughes9002 lol my bad. By update I mean my thoughts on the video
Sorry I just went with the flow 😂
@@brendonhughes9002 all good 👍. This is a very well thought out video.
4.2K views 6d ago
Great study!! I knew you would cover it so completely I would learn something new! We were lucky to have the winds be only 125 to 140 (gasp!). Imagine if those 184s made it to the surface.🤯
Thank you! Yes, thank goodness those 180+ mph winds didn’t make it down to the surface!
You should make a video on the july 19, 2018 Table Rock Lake, Missouri Derecho. This wind storm came out of nowhere (it occurred in a marginal risk) and resulted in 16 deaths from a large boat sinking in the lake. Definitely a very interesting storm system, and I'd love to see an in-depth review on the storm setup.
I remember that event well; I’ll add it to the list!
@@ConvectiveChronicles I recently heard of it, and I was super surprised because I went on vacation with my family on that lake last year around the area where the boat sank. I never knew that the area had such deep history. Ive been reading the Service Assessment on it recently.
I just discovered this channel. It makes my nerdy little heart happy 😁
I deployed to Iowa after that event. I'm amazed more didn't die, considering all the downed old trees, but thankful. And thanks for the review of this weather process.
Hell yeah super excited to watch this.
Watched this begin in SE South Dakota, when I got into work that morning. The extreme southern end of the gust front pushed through my location in Omaha right at 9 AM. Minor reports of wind damage, but nothing like what was developing over western Iowa, about 100 miles north of us. Was saddened, but amazed, as the derecho moved into Cedar Rapids, my hometown, in the early PM. They had a long lead time to watch this approach, knowing there was nothing to really do but wait for it to arrive! Thank you for the chalk talk!
I lives through this. I’ve never seen anything like it. 30+minutes of 120mph winds was insane.
These Derechos that Iowa had in 2020 reminded me so much of my sets of severe thunderstorms and freak severe thunderstorms that I quite often get when we get cold air aloft summer- on a good season.
Great stuff, Trey. I'll be honest I knew very little about derecho's before this, so I'm so glad you did this case study. Awesome, as always, my friend!
Thank you, Rhi!
I was working outside when this developed. Had no idea it was going to be the massive deal that it was. That yellow square on the peak wind gust map right below the "I" in Kansas City is centered right over my house. I was working 25 miles to the west, left, and drove 90 MPH down I-70 trying to get home before it hit. It hit my truck about 1/2 mile from home. I thought sure it was going to blow me off the roadway.
Dang, that’s crazy
Derechos are so interesting! Learned about them first hand living in va in 2012 and lost power for a week in 100+ degree days. That would be another really interesting one since the derecho was never expected to travel as far as it did, and it took advantage of all the available energy! It’d be cool to see an analysis on that sometime you want another non-tornado video
The 2012 derecho is on my list!
This is by far the worst derecho that I’ve ever heard of! Cedar Rapids, Iowa being hit with winds up to 140mph. That’s equivalent to a category 4 hurricane. That’s absolutely insane for a line of thunderstorms! I’ve seen some really nasty thunderstorms in my life with winds over hurricane force. However, outside of a thunderstorm dropping a violent tornado, these were the most dangerous thunderstorms that I’ve ever heard of. While every death is a tragedy, these storms could have much deadlier than they were. This video is the best scientific analysis of a derecho event that I’ve seen.
I love your videos! So fun to watch and explained in a way that’s easy to understand. I’d love to see more derecho case studies! One that has fascinated me is the 1999 Boundary Waters derecho event. Thanks for your awesome content! 😊
Thank you! This derecho case study was definitely a little bit more difficult to put together, as derechos aren't quite as intricate meteorologically and behaviorally compared to tornado/supercell events. But I do have some more derecho case studies planned in the future, and I will add that one to the list!
@@ConvectiveChroniclesthank you for response and adding the boundary waters derechos to the list! I’m looking forward to your future videos about this weather phenomenon. I also love the tornado/supercell analysis too!
Weird how similar an area this occurred to the most intense portion of the july 11-12 2011 derecho which was also very intense with winds of 120+ mph
We got a lot of these in 2022. (Ne montana)
.
We had 4 days in a row being the highest spc risk
Each time... it went qlcs wind bag VS super cells
.
We did get a night time ef2 near ophiem however
These videos are so great. I remember watching this event while it happened
Thank you!
As a Des Moines resident, I remember this storm like it was yesterday, especially the resultant weeks-long power outages that not only completely murdered my freshly bought groceries, but also turned my Apartment into the Sauna of DEATH!
Sadly what I had to deal with still pales in significance to what many others suffered as a direct result of said storm system, particularly in Cedar Rapids, where the Derecho's wind damage was at its worst.
Man, I can’t imagine having no AC in the summer in the Midwest! That had to have been unbearable.
@@ConvectiveChronicles You have no idea, buddy (nor would I want you to either. It was so horrible I had to take refuge at a friend's place for a few days [they got their power back before we did due to their location being in the downtown area, and thus a higher priority in terms of grid repair and restoration efforts]).
On the bright side, the view of the night sky was nice (more stars visible than usual thanks to such widespread blackout conditions).
I wish I lived in the Midwest and experience these awesome storms. I live on the Massachusetts coast so any thunderstorm that gets close dies almost immediately because of the cold Atlantic Ocean. Nor Easter’s are cool though
Nor'easters are very cool!
I'd love to see a case study of the June 2012 Derecho that crushed Ohio. Probably the most extreme weather event I've seen in my life.
What I found interesting is I live in Omaha and we never got a direct hit, but still had severe winds that nocked out power to tens of thousands. All thanks to a gust front. I don't think we even officially recorded any rain.
I remember this, by time it got to SW Ohio it wasn't that bad. Still windy as hell though
Excellent case study man. Thanks!
Thank you!
Wow, you do a great job of presenting information in an understandable way. I always assumed all of the straight line winds were caused by outflow, but learned differently from your video. I had no idea that there is a rear inflow jet that gets bent down. I really enjoy your videos. Thanks!!!
Thank you so much!
Amazing video man. Was extremely well done, and throughly explain. Later on that year, I experienced a derecho event later on that year on October 7th 2020, and scared the crap out of me as it was not really forecasted.
Otherwise, amazing video, cannot wait to see a new case study
Thank you for the kind words! Yeah, these derechos can be very difficult to forecast.
Ya your welcome.
Derechoes aren’t easy to forecast. I have a terrible time forecasting them c
I remember it being peaceful in central Illinois and I was working outside, looked to the west and I saw what could only be described as a picture I saw out of the dust bowl in history class. I got in my work van just in time for it to violently slam shut
We didn't have power for weeks after this storm and it was during covid. 2020 was a crazy year
2020 was a crazy year. Can't imagine what that was like without power for a long duration during the summer in the Midwest.
What a super educational video series, I applaud at you. Thank you so much, coming from an academic with a Phd in another discipline
Thank you for the kind words!
Thanks!
I really appreciate it; thank you so much!
Great stuff, hope you do some more - looks like we share some similar approaches to chasing - I’m also a fan of the local forecasters’ text-based materials earlier in the day
Thank you! I do occasionally read the AFDs, especially from some of the offices who go really in depth with their discussions, like Jackson and DFW.
Speaking of "ridge of high pressure", progressive derechos happen along the edges of heat domes. This is the reason why derechos mostly occur in late spring and summer. This one was no exception.
Question: what changed as the derecho came into Northern IL, especially the Chicago suburbs, to trigger the QLCS tornado outbreak?
That's a good question, nothing really sticks out. Perhaps a slightly more favorable low-level shear vector orientation with respect to the line, which can cause an uptick in tornadic circulations along it.
I always saw this sort of front of 'flames progressing through a puddle of gasoline' effect with these on radar and just sort of assumed these occurred when a disturbance upstream of really high cape set off a domino effect that traveled downstream in a weakly sheared environment.
This was a good video in that it showed the real detail of the mechanism here, particularly in where the most intense winds came from. I don't think I properly understood DCAPE and the effect of a capping inversion blocking winds from above it like this like this until now.
Thanks so much!
I would love for you to eventually do a study of the October 24th 2001 outbreak if you can. It was late season but so significant in the amount of tornadoes and wind damage produced. The town I live in southern Michigan was impacted. It solidified my love of severe weather.
I'll add it to the list!
Had bought my first house after graduation in Ames Iowa. My coworkers worked in cedar rapids so when it hit me i was able to warn them what was coming. It was insane. Got thw last generator at Menards. Moved it around the neighborhood to keep food good.
I now live in Janesville WI and my mother in law could see the recent tornado in Evansville. Throw in I was on highway 30 directly south of the marshalltown tornado (only time I've seen tornado emergency pop up on my phone) I've had an interesting last couple years of weather.
Great case study. 👏 What role, if any, does the amount of DCAPE have in a supercell environment?
Thank you so much for the kind words and the Super Thanks! They are much appreciated!
The higher the DCAPE in a supercell environment, the more likely you are to have supercells that produce abundant outflow (i.e. outflow-dominant supercells). As a result, tornado production tends to decrease in high-DCAPE environments, as the supercells will likely produce strong outflow that undercuts the mesocyclone region.
I know it's the second time I asked what you think on future systems, but I like hearing from someone who has legit knowledge in the field. Does day 9-10 (0z run of gfs at around hour 237) look like anything to watch for. And thank you for the videos I greatly appreciate your very detailed analyses!
Thank you! Yes, I'm definitely keeping an eye on next week. There's some pretty good agreement amongst models of a very potent trough moving in around that time frame. Of course, it's way too early to nail down details, but I am keeping a close eye on it.
Well done and I learned a lot. Thanks. I think I’ll need to see a three dimensional computer sim version to be
able to understand the rear inflow jet formation and maintenance. Help me Dr Orf!
Thank you! I agree, that would be awesome to see!
This might be a dumb question but I always assumed that downdrafts that cause strong surface winds originate from very strong winds aloft, but in this instance the winds through the atmosphere on most soundings seemed to be between 20-45kts. Obviously the rear inflow jet is the cause of the huge surface winds but how can that develop so potently with sort of average flow in the low and mid levels? Or is that not really a meaningful consideration with these events? Also with which types of storms are strong surface winds caused by downbursts of strong general flow aloft, and which are caused due to the rear inflow jet? Thanks a lot and keep up the great work!!!
Not a dumb question at all! The rear-inflow jet is the result of storm-based processes rather than strong atmospheric winds. I'd liken it to a hurricane, which strengthens its winds basically on its own as its low pressure center comes together; the winds don't come from strong flow aloft (weak wind shear favors hurricane development/intensification). It is similar for these derecho cases; the low that develops aloft as the composite updrafts tilt backward with height strengthens the winds that converge toward it. It's likely in this case that the low pressure aloft was unusually intense/persistent, allowing winds to continue to strengthen with time and eventually reach the surface.
Rear-inflow jets only develop in these MCS/bow echo cases, so it's only a consideration for surface wind strength in these cases. If we're talking about lone storms (e.g. supercells or random multicells) or complexes that don't involve a rear-inflow jet (e.g. clusters or other linearly organized features), the strength of the winds aloft have more of an impact on surface winds via downbursts.
@@ConvectiveChronicles Super helpful! Thanks for taking the time to answer!
Always wonder why and how this derecho had a 140 mph gust. The storms pretty much combined into a front at the same time with the extremely strong low level and rear inflow jet. Basically found out now. Thank u. Great video as always.
Thank you for watching!
I'm guessing the upper level high helps to ventilate the storm. The same way it does in tropical cyclone?
Actually, the high does not have a direct impact on storm behavior/intensity with these MCS/derecho cases as it does with tropical cyclones. The only part the high plays in these setups is that disturbances rotate around the top of the high and help initiate storms ahead of them.
@@ConvectiveChronicles oh ok appreciate you clearing that up for me. By the way, your case studies & breakdowns of imminent severe weather are easily digestible for people like me.
@@bradrandolph9631 Really happy to hear that, thank you!
What is the difference between a QLCS, squall line, MCS and MCV
Really, MCS/QLCS/squall line are interchangeable for the most part. If we wanted to get really technical, there are slight differences, but they all describe a solid line of thunderstorms. An MCV is a remnant cyclonic circulation that develops on the backside of an MCS.
You should do a video on anticyclonic tornadoes particularly those associated with a left moving anticyclonic supercell. There have only been 5 documented cases of a tornadic left moving supercell so it is very interesting looking at what unusual weather conditions you need for one. Iirc there is no known video footage of one and not all 5 of those tornadoes even have a picture.
Interesting idea, I'll add it to the list.
I've been through alot of derechoes living in Minnesota.
Iowa in August doesn’t need a boundary for moisture to pool along. They have extreme moisture from corn sweat.
That's a bit of a misnomer...the "corn sweat"/evapotranspiration only adds a tiny bit to the moisture and is often negligible. Multiple research papers have shown that some sort of stationary front is quite common for derecho formation, as moisture pools along or just north of it, yielding the formation of numerous storms and, eventually, an extensive storm complex.
140mph is low EF3 tornado winds. Is it just me, or did the structural damage not seem up to par with that? I’ve seen EF3 damage and cars are tossed and the buildings look much worse then the damage photos I saw from this derecho event.
Well, remember that 140 mph tornadic winds are different than 140 mph straight line winds. The tornado is probably going to be more damaging due to a number of factors.
You seen any of the grain Silos in between Cedar Rapids and IA City? Definitely EF3 damage.
Critically underseen vid and channel it seems. Very glad I heard ab u from Alferia. I enjoy his content but its more on human impact rather than the true nitty gritty of it all
Thanks so much!
I still remember waking up the next morning just wondering what happened. I live in Eastern Ohio, and I saw what was left of it. High clouds lit by the sunrise and a bit of a breeze, as if that storm was letting out its final, dying breath. Absolute monster, that thing, and it went ignored by the media between the continued impacts of the plague and the Presidential Election antics.
Used to live in CR. Moved beforehand. Have family that lives there. They lost their house to a tree falling on power lines connected to the home. Started a fire. CR doesn't look the same because of this event. Have a good one!
Dang, that’s crazy…hopefully they made it out ok. Thanks for watching as always!
Ohoho yes this event. This one I remember well but here's the kicker, I was out chasing the stuff around Albany that you see there so it wasn't till I got back home that I really got to see full scale how the derecho and aftermath of it was progressing after it was around Iowa. Granted I did keep up with it a bit while out chasing but I could only do so much while trying to focus on my end. Unfortunately I chased around Albany itself and not the Northern crap that did get the tornado report in the end but it was rain wrapped and very brief from the NWS survey AFTER the fact. Video I got from that event wasn't even good enough for me to post to YT. :|
I think the one thing about this event that was wild is still the shear amount of tornado reports and just the amount of chaos that was happening around the Chicago area during the event itself cause it was tornado central and tornadoes around the metro. I mean it's been a while since we have seen something that intense and some of the wording I remember the NWS out there was putting out in the Chicago area and region was quite strong and immediate showing how intense this was.
Still Cedar Rapids and area of Iowa just got smoked. Some of the home webcams of the event that even today still float around on twitter are incredible and just seeing everything go from dead calm and minor little rain to BOOM with 80+ mph winds and then the rain and damage after the 2-5 minutes of insane hurricane force wind was nuts.
Yeah, the Chicago area did take a beating. There were quite a few tornado reports from a combo of spin-ups along the line and storms out ahead of the line. The environment wasn't super supportive of tornadoes, but there were quite a few reports.
I watched quite a few of those home camera videos in my research for this event from Cedar Rapids, just incredible footage.
It has been 3 years since this happened.
the only thing that was costlier than this in the US that year was Laura in August as well
47:26 giga chad windbag
How about a video on the evolution of forecasting🤔
That’s an interesting idea
@@ConvectiveChronicles hire me
45:37 WOAH my jaw dropped
I noticed that you tend to circle your mouse cyclonically, haha!
Haha yes!
When you see a red wave on a weather map (or a political movement) know that damage comes with it.
Got new headphones so I can hear lol
😢😢😢😢😢😢
Corn fueled weather.😂
I was in Cedar Rapids when it hit, that was fun living without power for 2 weeks. Can we do it again?
Thanks!