Powerful gusts whip area after 82-degree high

Friday delivered long-awaited 80-degree warmth to the Chicago area. Powerful south
winds extinguished lake cooling and gusted above 40 m.p.h. outside thunderstorms that
swept in waves. The mercury reached the day’s high of 82 degrees at 1:48 p.m. at O’Hare
International Airport—a reading 20 degrees above normal and the first time in 186 days
that temperatures topped 80 degrees or warmer. But that heating, in combination with the
most humid air of 2008, fueled thunderstorms. Dew points in the low and mid-60s
assured plenty of atmospheric moisture for storms that towered to 51,000 feet and sent
lightning bolts within a 200-mile radius of Chicago, charging earthward at just under
2,400 strokes every 10 minutes about 6 p.m. The storms raced across the area at
incredible speeds—moving at 60 m.p.h. much of the afternoon and evening while
bombarding some northwest and west suburbs with hailstones the size of golf balls.
Hardest hit were the Rockford area and Livingston County southwest of Chicago.
Naperville and Aurora reported hail nearly 1 inch in diameter. Storm gusts at Von Steuben
Metro Science Center in the city clocked 66 m.p.h. winds about 7:30 p.m.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune