Severe storms struck much of the Midwest on October 18, 2007. The images in the first column at right show the location from which the video was taken. The second column contains links to the video (QT, 320x240). The camera timecode was later compared to time.gov, and time labels were placed in the video to show the UTC times, hopefully accurate within a few seconds. Locations here estimated from Google Earth.

• First location: I-57 (southbound) rest area, looking southwest. Approx. location 39.931 N, 88.305 W. Time of video was 23:00 UTC. Cloud base with small (at this distance) lowering was evident.

• Location 2a: southwest of Pesotum, IL. Approx. location 39.903 N, 88.284 W. Location 2b: somewhat farther down (southwest) on Chestnut St. Approx. location 39.898 N, -88.2908 W. Time of video: 2311-2318 UTC. The storm had obvious rotation, and was apparently backbuilding as the base moved little despite cell motions reported as NE 55mph. Distinct rain cores developed, consistent with the above. The most prominent lowered base and evident wall cloud is towards the end of the video (the rapid visibility change is due to use of the car A/C!) but no tornado was seen. Any weak circulation at the surface would likely not be visible from this location, however.

More data here when I get my hands on it..
The UIUC archive for 10/18 is here (starting at 19z).