April 30, 2003 – Tornado intercept in Northwest IL

Today’s setup looked very interesting and promising, but would I be able to chase today? The models seemed to be all over the place with the system, so I wasn’t sure where this thing was going to strike. The wonderful CAPE values were forecasted to make a welcomed return to the area with values around 1500-3000 depending on the location. Dewpoints were also looking good and were on their way to 60+ without even looking at the models. Lifted indices were also forecasted to be anywhere between -4 and -8, so there was definitely some very nice instability. Finally, the helicity values weren’t too good in central IL, but in northern and northwestern IL they were looking much better with values projected to be between 200-350.

My chase partner Darin Kaiser usually has Wednesday’s off from work, but he had several folks set up appointments with him so chasing was put on hold for awhile. I continued to monitor the situation throughout the morning and pondered several target areas in case I could chase. Obviously, I knew we couldn’t chase in northwest Missouri or southwest Iowa as it was just too far away. I kept looking at northeast Missouri and southeast Iowa though as the models were showing some promising signs for that area. The SPC Day 1 outlook painted a swath of moderate risk from eastern Kansas to northeast Illinois. I wasn’t too confident in that forecast, but decided to see how it all panned out. As I was eating lunch, an MCD was issued for the area regarding possible thunderstorm development.