Thunderstorms towering more than 10 miles above Illinois raced across
the state at 50 m.p.h. Wednesday afternoon and evening, unleashing
downpours and producing powerful winds and lightning across an 800-mile
swath of terrain from Wisconsin to the Oklahoma Panhandle. Lightning
data indicated nearly 2,000 cloud-to-ground strokes were occurring
within a 200-mile radius of Chicago late Wednesday-a total exceeding
16,000 strikes was tallied in just six hours' time. The torrential
downpours late Wednesday evening deposited 1.33 inches in just 15
minutes at Milledgeville in western Illinois, northwest of Dixon, and
caused 6 inches of standing water at Morrison near the Quad Cities.
Late-evening storm gusts downed power lines at Mt. Morris southwest of
Rockford as the squall line marched toward the Chicago area, which had
first been placed under a tornado watch around 6 p.m. Wednesday.
Tornadoes in the Heartland
Nearly two dozen reports of tornadoes had been filed with the Storm
Prediction Center across the nation's Heartland as night fell Wednesday.
One especially deadly twister was produced by a rotating thunderstorm
known as a supercell that forecasters tracked across northern Missouri
into west-central Illinois for nearly four hours.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune
