2026-04-17 REPORTS: MN/IA/IL/WI/MO/KS/OK

[Luke Penney]

My chase started in east Iowa, then went along the Illinois/Wisconsin border to the Rockford area. I tracked one supercell/cluster almost the whole time, with some viewing of the line of storms that followed after it (and eventually merged with it) toward the end.

For the first part of the chase, I didn't see much, due to a combination of lots of rain, northwestern Illinois being hilly and forested, and me ensuring I was giving the storms plenty of space because I knew how volatile the atmosphere was that day.

Partway through Illinois, the terrain improved a lot and the rain improved a little, and I was able to see more of the storm's structure. (Unfortunately, it was always a wet rear-flank downdraft. From what I could see of the south end of the RFD/updraft horseshoe, there were times when it wasn't at all hard to picture a tornado happening at the north end of the RFD that I couldn't see.)



My favorite shot of the day was this short video, as I think it gives a great sense of the scale of the storm (even if it's a little out of focus).
View attachment IMG_2953 - Compressed.mp4

Near Rockton, Illinois, I suddenly saw a funnel materialize out of the rain - quite possibly the Rockton tornado. I tried to pull over and take a photo, but unfortunately it had already disappeared, and all my photos show is rain.

I had pretty much finished up the chase for the day when I received a sudden lesson in the dangers of damage caused by previous storms. On the highway between Beloit and Janesville, there was a tornado-warned line of storms oriented northeast-southwest with a clear hook echo to my north, and a new hook forming to my southwest and coming my direction. I, on the north-going side of the highway, was planning my escape route to be to turn around and go south with the next exit - when I suddenly saw that there was an overturned semi-truck on that south-going highway with lots of cars stopped behind it. I couldn't see a safe route to drive away. Fortunately, there was a weighing station beside the highway that I sheltered in. The storm there didn't end up being bad, but I wasn't happy that I'd ended up in a situation with no obvious escape route.
Afterwards, leaving the highway and taking other roads, I ran into three streets blocked by downed trees.

Fortunately, that was the end of the complications, and the travel home was smooth.

(Edit 2026-04-19: Added one photo I'd intended to include originally.)

 

[Mikey Williams]

Full chase log HERE: Mesoscale Mikey Meteorology - April 17

This week is a week that I am glad is over at last, for sure a trial week and a test of character, faith, and passion, as I had to sit out most of this amazing sequence due to not only some academic responsibilities, but bad social and forecasting decisions that led me to miss 4/13, 4/14, and 4/15, including both of the super photogenic tornadoes here in Iowa that many of my collegues saw. Multiple significant tornadoes kept battering the surrounding counties around my home in KC throughout the week while I was helplessly away. This, combined with some recent family and academic challenges, and undealt past issues, created one of my lowest points in quite some time, and a tempest no supercell could produce. But, I knew that I had another shot still to go, April 17th. So I found the courage, to re-gather my gear, find gratitude, repatch my spirit, and work with my beloved team and see what we could come up with.

I got up on the 17th with decent setup expectations as we were now almost certain that pre-frontal spinners would form ahead of the cold front, but there were a couple flies in the ointment. Number one, we could not leave Ames until 12:30 as one of our team members had work, and with my anticipation of the main shortwave arriving into the IA/IL/WI target area by 2 pm, I knew there was a chance we were cooked on trying to get there in time for the big show. Number two, even if we did get there, I had concerns about storm clustering and if supercells would suffer too many mergers. I also did not like how the shear seemed to get worse with time. All five of us, esspecially Alex Voss and I were pretty on edge about our hometowns. Alex was from Wisconsin and was in the cigtor risk and just had an EF3 in his state a few days prior, and my town, Kansas City, was under its first 4/5 "Moderate Risk" since the personal EF4 hit Lawrence and Linwood, KS in May 2019, with us also having active storms during the week. By the end of the day, not a single one of the five of us didn't have a tornado at least somehere near their home, dispite us living in three different states.

We left Ames, blasting east towards Cedar Rapids, targeting supercells that were initiating over the city. On our way, the mighty anvil of the supercell we were targeting, (the southern of two large ones), appeared. This storm would go on to produce tornadoes, including the EF2 that sadly turned tragic in Lena, IL. It became appearent that our chances of catching this thing were slim, as we could not seem to break 29 miles of distance from it, so we began focusing on stuff to our west. Initially we head for the cold front stuff, but see more prefrontals going up that looked to be turing into mini supercells as they got near Cedar Rapids. We did observe a wall cloud with one before we had to let it go and switch back to going after the cold front stuff. We had two tornado-warned segments go up, and we briefly stopped to observe the spectacular green hue. Getting further east, we were able to see some wicked shelf structure materializing. The storm eventually overtook us and became a significant-wind monster, pruducing winds near 90 mph as it pushed off to the northeast. We saw another book-end meso thingy with a confirmed tornado to our southwest, and decided "why not?", and pounced on it since it was early. The anvil structure on the way was beautiful.

We pull up to the storm and let it go by us, and with some mild wind, a positive CG lightning barrage ensues. When we decide to leave, we find out we had gotten stuck the whole time after pulling over. We try everything, pushing, reversing, sliding, true college bonding. I even tried to take handful after hndful of gravel and put it under the tire for traction, but to no avail. But thankfully, a kind local came to pull us out of the mud for free! Though their partner seemed less than happy. We then celebrated the high-stress and difficult chase day with Culver's, a prize of the Midwest. I found the mud and our team effort to try and get out of it while being drenched in stratiform rain under a rumbling, mammatus-blanketed anvil of a tornadic storm with clear sky rolling in kind of a poetic way to end such a week, and representation of what it had been like. I come out of it not the same each time things like this happen, ussually once a season or two, whether in my chase days or bike chase days, but in the end, the storm did not take Mikey. And I will be a better person, friend, colleague, chaser, and meteorologist because of it. It was a tough chase and week, but a worthy one. While I must remain responsible and humble, and am hungrier than ever and back for another fight later this season.