04-30-10 CHASE LOG: IA/IL/WS

Not too special of a chase overall with a lot of miles put on, but it was fun regardless. Peggy Willenberg, Melanie Metz, and I left Council Bluffs, IA after bagging a tornado and some amazing supercells near Washington, KS the day before. Our plan was to get ahead of a cold front and chase a line of storms racing east of Des Moines, IA already by midday. We raced east on I-80 into eastern IA and finally managed to get ahead of the storms near Iowa City, IA. Storms were moving to the northeast at 60-65 mph so it was nearly impossible to stay with them, so our only hope was to get ahead of the line and wait for a strong storm to come up at us from the southwest. A few finally did as we approached Davenport, IA and I did manage to get some video and screen captures of the occasional cloud to ground lightning. Storms that managed to stay discrete did have nice bases and even a few visible updraft areas, but everything was rather embedded and tough to see. The Storm Prediction Center issued a tornado watch for much of IL into southern WI as we got into eastern IA as this area was very highly sheared and destabilizing ahead of the front. However, it became fairly clear as we entered into IL that storms were going to be more of a linear mode along this front with the strong forcing and a 100 knot 500 mb jet, albeit in a very highly sheared environment. A decent storm developed to the north of Sterling, IL and was moving northeast towards southern WI. We traveled north on I-39 and I-90 to near Janesville, WI where we intercepted and watched the storm pass, which had a nice base and cloud to ground lightning. After that, it was time to start heading home as everything became very messy. As we passed through Madison, WI, I noticed on radar some rotation coming at us from the southwest with what looked like some sort of mesolow. We ended up intercepting this storm near the Arlington, WI exit where there was a lot of motion and even a wall cloud that I did not get a picture of since I was driving. This storm later produced a tornado to our northeast in Green Lake County, WI.