While the moderate risk was way out in Wyoming and Nebraska, parts of Illinois were under a slight risk for Saturday. The forecast models were predicting CAPE values between 2000 and 4000 j/kg, which is probably the highest they’ve been all year. The atmosphere was definitely juicy and very unstable, so anything that would get going would develop rapidly. However, when looking at the 7:00am CDT (12z) upper air sounding, it showed a cap value of 3.2. That’s a pretty decent sized cap, so storms would really need to punch through that to fire up. Needless to say, I was optimistic that something would fire up in the late afternoon/evening.
Around 10:50am CDT, I heard someone calling me on the local 146.760 ham repeater, but they were using my old callsign. I suddenly realized that it was Chad Gard from INCHASE, so I went back to him. While we were talking, I was alerted of a mesoscale discussion for IL/IN/OH/KY. I informed Chad about this and even read the entire statement to him. (which probably scared any non-chasers who happened to be monitoring the frequency) 😉 Anywho, he decided that he was going to head to Springfield to check on data. He offered to pick me up on his way through, but I declined and told him I would just wait for the storms to fire up around here. Chad also told me that he finally got his APRS tracker working, so I decided to look him up on the Internet to see if it was working. Sure enough, I pulled up his position and tracked him all the way to Springfield. 🙂
I decided to continuously monitor the radar/satellite maps as best as I could. While looking at the radar loop from ILX, I noticed an outflow boundary between Bloomington and Springfield that was moving to the northeast. In reading the Chicago area forecast discussion, they also mentioned this boundary. Taking a hunch, I looked up the special upper air soundings and sure enough, ILX had sent one up at 1:00pm CDT (18z) to check out the atmosphere. The cap value had increased from 3.2 to 5.7, ouch! This was severely suppressing any thunderstorm development. So now the wait was on to see if the cap would break or not.
Around 5:30pm CDT, I noticed a few cells in Western Illinois that were trying to go up, but they seemed to just be dying as soon as they did. (darn cap) A few minutes later, a small cell popped up right here in Champaign county. It didn’t stay up very long, but soon after another cell popped up almost in the same spot. Was this the beginning of the cap finally eroding? Around 6:55pm CDT, I decided to head out and see if I could intercept one of these cells. Just after I left, the weather radio went off for a severe thunderstorm warning right here in Champaign county! 🙂 I headed south of town a few miles and went west a ways so I could get a good shot of the storm. I eventually ended up in the southwest part of the county (400E, 200N).
I got out of the car and started taking pictures of this awesome looking supercell to my ESE. I had to get out my map to make sure that I was actually in Illinois and not out west in the plains. It was so cool to finally see a supercell here in Illinois without a bunch of low-level clouds in the way. I started looking around and to the west was an amazing sunset that warranted more picture taking. Around 8:00pm CDT, I turned on the weather radio to get the latest conditions and the dew point in Champaign was 70 degrees! I started heading east towards the supercell hoping to get some lightning, but never did see any from the cell. Then I heard someone calling me on the radio and realized that it was Chad. (what’s he doing back here?) 😉 He had picked up Scott Kampas and just headed east to try to intercept this nice cell I was on, but never really caught up to it. They were getting hungry, so we decided to meet up at the local McD’s for dinner.
After shooting the bull for awhile, they decided to head out to take Scott back home before making their journey back home to Indy. I arrived back home around 10:30pm CDT.
I have to say for as little distance as I went, this was one of my most nifty chases. It’s not often that we get an unobstructed view of a supercell here in Illinois. No, I didn’t see any hail, tornadoes, or even rain, but the structure of the supercell was simply awesome.
Hmmm, thanks to mother nature for finally breaking the cap so close to home. Also, thanks to Chad Gard, Joe Walters, and Scott Kampas from INCHASE for the great conversation/chaser convergence.
Total Chase Time: 3.5 hours
Total Chase Miles: 40 miles