Storm Brings Record Rainfall in Midst of Chicago Heat Wave

Overnight rains dumped nearly 7 inches of rain on Chicago early Saturday, breaking a record for the city, canceling flights, and causing parts of highways and train lines to shut down.

Those looking for some kind of a break from the heat of the last week got it overnight -- a rainstorm that dropped temperatures into the low 70s. But like the heat wave that preceded it, this rainstorm was anything but ordinary.

Triggered by a frontal boundary and a highly unstable airmass, powerful storms erupted just before midnight with cloud tops as high as 60,000ft. A line of storms extended from the lake westward into downtown and across several northwest suburbs. Conditions quickly deteriorated with torrential downpours, frequent lightning, and gusty winds. To make matters worst, the storms were barely moving, a recipe for flash flooding. The rainstorm was anything but ordinary with a Flash Flood Warning issued shortly after midnight.