Acting on a moisture-laden atmosphere, heating by ample sunshine triggered widely
scattered thunderstorms across the Chicago area Friday afternoon, and the storms
continued into the evening hours.
While many areas went rain-free, other locations experienced very heavy downpours. A
weather observer in Arlington Heights recorded 3.26 inches of rain between 6:30 and 8:45
p.m., while in the late afternoon, an observer in Wilmington, just south of Joliet in Will
County, measured 1.90 inches in one hour. As a large heavy rain area developed and
persisted over northern Cook County, the National Weather Service issued a flash flood
warning at 8:45 p.m. for that area.
ADDITIONAL HEAVY RAINS POSSIBLE
With a frontal system acting as the stimulus, thunderstorms could trigger rainfalls in
excess of 2 inches at many locations in northeast Illinois Saturday through Monday.
--By Paul Dailey, WGN Weather Center Meteorologist
