The Plainfield, IL, F5 Tornado of August 28, 1990: A Case Study

In-depth discussion of the infamous Plainfield, IL, F5 tornado on August 28, 1990, which remains the only F5/EF5 to strike the US in the month of August since records began in 1950. In this video, we'll take a deep dive into the meteorology behind the event to determine how the Plainfield tornado may have happened despite, at first glance, a seemingly unfavorable environment for significant tornadoes. We'll also discuss some interesting features of the supercell and tornado, as well as compare it to another well-known Illinois violent tornado case that had a very similar background environment.

Thumbnail images via NWS Chicago.
---------------------------------------------------------
Chapters:

0:00 Introduction
3:21 Meteorological discussion
10:15 Sounding analysis
16:25 Radar analysis begins
17:41 Discussion of initial outflow dominance
20:19 Re-ingestion of outflow boundary
21:49 Similarities between Plainfield and 5-5-19 Tahoka, TX, case
24:07 Discussion of extreme CAPE not being main factor
27:57 Lightning anomalies in Plainfield supercell
32:44 Vortex constriction immediately preceding intensification to F5
34:14 Analog - Roanoke, IL, F4 - July 13, 2004
36:54 Wrap-up
---------------------------------------------------------
Resources:

---------------------------------------------------------

[wxjustin]

Every video you make is pure gold. An entire senior level college course could be taught just using your videos

[matthewhales]

My dad issued the severe t-storm watch for that storm. Plainfield and Windsor Locks never stopped haunting him. He was able to watch this video before he died two weeks ago. He was super impressed with your analyses of notable outbreaks and events. May 31, 1985 was another great video he enjoyed. He and I had a trip planned to explore the east coast that summer, and were leaving on June 1. The morning we were to leave I awoke to "change of plans, we're going through Ohio". We toured the damage in Niles. For 14 year old me, it was pretty intense and memorable.

[nicoleayala]

Thanks for covering this. I grew up in Plainfield on the footprint of this thing and it was very much a life-changer for everyone in the area. As kids in Plainfield most of us grew up weather aware, learning from a young age how to read basic reflectivity, identify basic cloud structures and having an understanding of storm safety protocols…and we were basically taught that the NWS isn’t gonna ever be able to catch and warn everything, so we need to be educated to take things into our own hands if need be. I think that’s the one good thing that came out of this tornado— it influenced the creation of a locally more weather-aware community that then moved other places and took their knowledge to new places.

[runt]

Man, Trey, I can't even begin to put into words how incredible this one was. I already forgot how much I learned from this video. The entire section on CGL polarity was completely new to me, I don't think I remember learning about Northwest flow cases at all, I've never seen such a powerful tornado out of such meager shear, and so on. You know I say it every time: I love learning something new from every video, and this entire video was education for me! Fantastic work!

A storm ingesting its own outflow boundary to consummate tornadogenesis feels so much like a basketball player throwing the alley-oop to themselves for the dunk. But it also makes sense that the winds that the storm is putting out will generally be faster than the storm itself so the outflow boundary will get thrust forward, it just seems fairly rare for it to stay aligned in such a way that when the storm can catch up to it, it's oriented in a way for it to ingest it. Needless to say, with that kind of extreme instability, it definitely doesn't take much!

The main thing that's crazy to me is how much of a difference only a few years made in weather prediction. Watching this vs watching the study about the infamous Jarrell tornado that was only a few short years later shows you how incredibly impactful some of these late 80s/early 90s events were for really spurring on the technological advancement into some of the systems we still use today. It breaks my heart to know that this damn thing didn't get a tornado warning until the vortex was already off the ground. Imagine how many lives could've been saved if there was just a bit of a warning.

Anyways, you continue to knock these out of the park, I'm gonna KEEP giving props to the editing and the scriptwriting because I really do know it takes a lot of time and effort and it shows! Keep it up Trey, can't wait for the next one!

[kandicejanusz]

Raised in Plainfield. I was 12 yrs old when it hit. Remember like it was yesterday.

[sNewWaveGeek]

I've studied this event for some time (having grown up not far from Plainfield), and your take of the outflow dominant / inflow ingestion dynamic was the first time I've heard such a take. Very intriguing, and thank you for sharing.

[dillyboyq]

Lets go it’s a GREAT day when Trey uploads!

Also it’s meteorological set ups like this one that make it seem almost impossible to be able predict tornadoes like that! So many things factoring in to be able to do that! Makes me truly respect SPC & how amazing they do in forecasting! Great analysis as always!

[sagemaster]

I specifically remember Tom Skilling talking about the raised threat level . I was 11 years old and riding my bike when the sirens started . I was so worried I fell off my bike and got my leg pinched between the front wheel and the front forks . Haha. So I always tell people I was injured in the Plainfield Tornado!!

[CeltonHenderson]

Great video man! From a meteorological perspective this is one of my favorite tornado events to study.

[kayeas]

okay… now this one was awesome. outdid yourself here!! loved that you mentioned the conservation of angular momentum playing a role in tornado damage. that and vortex mechanics are some of the most intriguing things to me about tornado strength/damage infliction, and I genuinely could talk about it all day. hope this is mentioned in the Elie case study! :)

[zachsteiner]

Now this is an exciting case review. Definitely one of the most “mysterious” significant tornado events. Excited to learn more about the unique environment that was in place for this to occur. Have a good day Trey, thanks!

[jbooth]

I was born after the tornado but I grew up in Plainfield, I went to the rebuilt Plainfield high school. My 7th grade science teacher was one of the football players who ran into the building and he said he was the last one to run into the hallway and as he shut the gym door behind him, through the little window he saw the roof get ripped off!

[ZZ_Trop]

The path is directly across the area that I worked for 10-12 years. Up and down 127th, 135th, down rt 30, etc. I'm intimately connected to the path as I was a landscaper, meaning I looked at the land like a landscaper. I know the trees, homes and neighborhoods that it destroyed like the back of my hand. Great video!

[brianneben]

I know these older events are harder to cover due to the lack of information, but you do a very good job in the detective role. Keep these case studies coming!

[SamEvans-at-sc_evans]

Absolutely superb analysis and context

[tornadotrx]

So good, one of my favorites from you cause of the forensics and analogs you used to really hit the nail on the head with how the tornado formed. This kind of analysis is really important cause it forces us to think outside our comfort zone with svr wx as these violent tors can really pop up in impossible conditions with the right interplay.

[mattschneider]

People forget a couple things about the local conditions at that time- 1) The CAPE values were over 8, 000 (I've never seen them that high anywhere), 2) The LI was -13 (also extremely low) and 3) Lots of low level shear from lake breezes. Add that together and you'll get large tornadoes.

[davidspangler]

Makes someone wonder how many storms use the environment they create around/ahead of themselves to become more potent. Awesome breakdown, thank you again

[CharlotteJones]

Watched last night and came back to comment this morning because I am still thinking about this video.

Very grateful for all the time and effort that goes into these videos. You clearly have such a high level understanding of all of this from all of your years spent studying and chasing and as such, do an incredible job spelling it out in a way that people like me can understand without struggle - I am not in the weather field at all, just have a budding interest and study it in my free time as a break from the health/fitness field, and I learn SO much from every single video you share. I find myself pausing, rewinding and rewatching explanations to make sure I have a full grasp on everything. Loved the old chase clips mixed in as well from the analog cases. Just such a stellar video and it is awesome to see your content continue to evolve. Can't wait to watch the 2024 season outlook!

[Zoots]

Lombard - the sky turned pitch black. Have not seen it like that since.