Nice breakdown. I've got to say this came as a surprise to Chicago. I'm sure they weren't expecting something like this to happen. You explained the meteorological process to this event perfectly.
Everything about this event is super fascinating to me including the setup, the location , and the storm behavior/structure. Definitely taught me a thing or two about MCV regimes since last night. A little mad I didn’t get up there to chase it, so big thanks for doing a video on this!
Hi Trey! Wow this is such a great video! I live in Montgomery, IL, right by where the first supercell formed and I *think*, according to that radar loop, it was the same supercell that went on to produce the tornado that almost immediately occluded near Stickney/Cicero. Just wanted to say I appreciate how quickly you posted this and I've enjoyed all your past content too!! I've always been passionate about weather but was scared to pursue it (I'm bad at math lol) so you're an inspiration! I will definitely be watching your definitive guide to skew-ts and hodographs so I can gain an even deeper understanding of this and past events :)
Thank you so much for the kind words; I really appreciate them! Please let me know if you have any questions on the skew-T/hodograph stuff; always happy to help!
Great summary Trey! I grew up a mile north of Burr Ridge, really wish I was there to capture that tornado. I actually called my family and made sure they were in the basement. My friends house was nearly hit too. Thankfully that tornado was not that strong, because if it was it would have been much much worse.
Thanks so much, Chris! Glad your friends/family made it out ok; very glad that tornado was on the weaker side, as that could have been an absolute worst case scenario for that part of the city.
Right along here in Chicago, I remember grabbing my cat and running to the basement. Your videos and breakdowns have inspired me to change my major in college, I am a rising junior!
Thanks for this! I'm really glad you explained the idea of entrainment causing the storms to not be as prolific as what may have been expected. I definitely noticed that on the ground. Because the storms were low topped, they were really more like rain showers. I was watching a tornado-warned supercell approaching my area for around 10 minutes and I didn't see a single lightning strike or hear thunder at all. If it wasn't for the wall cloud that I could see approaching, it would have looked like any old rain shower. After the storm passed, there were blue skies, and I could see the entire cloud top and it was not very high at all. Also, the TDWR data was absolutely fascinating. Having very low-level and minute-by-minute updates from not one but two TDWRs is something I kind of take for granted here, but it's really useful when we have storms.
Thank you for watching! You're absolutely right; in these effectively low-CAPE environments, you'll often see "supershowers"...rotating storms with very little to no lightning/thunder. Really fascinating how these supershowers can still spawn some notable tornadoes.
As a weather geek, thank you so much for sharing your knowledge and details on the event. Enjoying learning a lot of new things and thanks for the links.
O'Hare is way in the northwest corner of Chicago. Only by a weird technicality is it even included in the Chicago city limits. It was one of the Elgin storms that moved east toward O'Hare. This terminal doppler radar station has to be somewhere around LaGrange or Brookfield, maybe even Midway Airport. The bean you highlight at 14:46 south of Aurora may have produced a tornado around Fox Bend Golf Course in Oswego. It's just listed as a damaging wind report on the SPC's storm reports page, but it's likely a tornado that downed trees in that golf course.
I’m saw a couple of disturbing, but not unexpected, anecdotal stories - one from a guy abt the his hotel staff’s response and one from a guy who was actually on a plane at Midway. Both felt that there wasn’t a timely or appropriate response to the warnings. Lack of weather awareness, complacency, delayed response to the situation, etc. Both of these guys were monitoring the situation themselves and saw things going south fast and were frustrated.
Yeah, I’ve seen a few of those stories…I’ve heard the sentiment that “Chicago doesn’t get tornadoes, so there’s no need to worry.” People are probably a bit underprepared there.
Just a correction - those storms on the NW side ended up being the ones impacting Ohare. Ohare is on the WNW side of chicago, you seemed to mention ohare when focused on the storms actually occuring near Midway, which is SW of downtown. So the super cells that went thru Elgin were the same that impacted Ohare
@26:42 since that was a terminal radar, is it possible the rest of the cell that the tornado was in was shadowed by the cell in front of it? not exactly sure where the MDW radar is so IDK
I don’t think that was the reason for the phenomenon I was explaining, but there was some issues resolving the storms as they came very near to the TDWRs, especially TORD.
Hey Trey, In the RAP proximity sounding analysis discussing the strong streamwise vorticity... you describe it as a QB throwing a ball. I've had a hard time visualizing this. Can this also be looked at as the "roundness" of the low level hodograph with the RM storm motion as the center? Wonder if a Mr. Talbot got in on the action. Thanks again, awesome content
Thank you! When I use the analogy of a QB throwing a football with a perfect spiral, focus on that "perfect spiral" part. It makes it much easier to catch for the WR...this is similar in the environment. Supercells maintain rotation by tilting tubes of horizontal vorticity into the vertical (see Figure 1 in the Markowski and Richardson 2009 paper linked below). Strong streamwise vorticity means that that the storm relative wind is blowing parallel to these horizontal vorticity tubes so that the supercell attains rotation from the get-go and can more easily undergo tornadogenesis as this vorticity gets stretched by the strong rotating updraft. Crosswise vorticity means that the storm relative wind is blowing more across these horizontal vorticity tubes, meaning that the initial storm updraft does not rotate from the get-go. Instead, the updraft has to manipulate this vorticity first before it can become a supercell: counterrotating areas of spin on the flanks of the incipient updraft develop, and then these can develop into rotating right- and left-movers. This is also unhelpful in aiding tornadogenesis, as the crosswise horizontal vorticity is not able to be immediately concentrated within the strengthening mesocyclone of the right mover. This is akin to a football thrown with a big wobble...the WR may have to bobble it a bit before catching it properly. I've also linked Cameron Nixon's hodograph article to help. Markowski and Richardson (2009) paper: eps.harvard.edu/files/eps/files/markowski_richardson_2009.pdf Cameron Nixon's article on hodographs: cameronnixonphotography.wordpress.com/research/the-storm-relative-hodograph/
Great video as always! Is there an archive of the autumnsky site? I have looked at the site a few times and haven't found anything about an archive. Thanks!
That was great. I think on the 12th I was sleeping off the overnight shift so when I woke up I was like damn. Especially since I mostly was exhausted and slept through a good portion of this event trying to watch it from Albany. ECAPE....that is something that makes sense why I never heard of it before, as that was something they never taught us at SUNY Oneonta and it makes sense since it's very new in a way concept wise to study. I mean that's gonna be interesting to figure out how the parameters shakes out and how it coordinates with storms and what you don't want to see in storms. It's sure as hell will be interesting when they get more knowledge and baselines for that. Also the detaching of the updraft was crazy ass cool. I don't think I ever seen that before.
I was wondering if you could do a case study of the 4-15-23 tornado squall? I was backyard chasing in it and got in 2 tornado warnings and an EF1 near me
I also use the College of DuPage weather resources, I've chased with them, and I actually once taught there as an adjunct......the setup of this event sounds similar to the unexpected NW Ohio tornado outbreak of Aug 2016.....there was I think a marginal severe wx risk out on the day of the event, but there was an MCV initially unaccounted for by weather models, and the tornado threat on the day of the event rapidly increased. We had multiple EF2s produced from one supercell, which thankfully did not produce once it entered the Toledo area.......last thought: that Burr Ridge tornado dropped 5 miles east of where I grew up. Two years ago on Dad's Day, there was an EF3 that missed my folks by 3 houses.....
Thank you for teaching me a few things. I only know the basics of the Skew-T chart, and this stuff is endlessly fascinating. I’ll be in Texas in a few weeks, maybe I’ll see you out there!
My brother saw the one that hit hodgkins across the street from his work, he said it kept going up and trying to come down but was unable to so that must have been when it lifted out of the area? Either way super scary knowing he saw it so close! I was listening to Andy Hill's stream and he mentioned it hit the shopping district which I thought meant there was a bubble between him and the tornado, a safe distance but I was wrong 😅
This is just a shot in the dark from an enthusiast, but maybe the quick detachment of the tornado from the parent storm was a result of the extreme low-level shear, perhaps accentuated by the relative shortness/weakness of the updrafts? (Less for the tornado to "root" itself to, in other words.)
I never heard about ECAPE before. Learned something new. The SRH values and hodographs had me going autistic yesterday lol. Anyway, at least there was some good videos that people captured.
There should be a lot more coming out about ECAPE in the future. Right now, it’s in its infancy, but it’ll be a very useful parameter once it does come into mainstream meteorology.
