Chill follows 40° plunge—biggest 2-day May drop in 6 years

This weekend opens noticeably cooler than its predecessors. There hasn’t been a Saturday in four weeks—since April 14th when the high was only 49°—with cooler daytime readings.
Saturday dawns with temperatures 40 degrees lower than Thursday afternoon’s 84° high—the warmest reading of 2007 to date. It’s the biggest 2-day plunge in May since May 10-12, 2001, when readings tumbled from 81° to 38°. May has hosted some eye-catching temperature pullbacks—some even more significant than this one. Back in 1925, residents endured a 57-degree May temperature plunge—from 94° to 37° between the 23rd and 25th.
Northeast winds gusted to 35 m.p.h. at Midway Airport and to 37 m.p.h. at the Harrison-Dever Crib three miles offshore as the chill arrived. Though south suburban Kankakee reported 81° at noon, the surge of cool air sent readings there tumbling to just 54° by late evening—a 27-degree drop in less than 9 hours!
--By Tom Skilling, WGN-TV Chief Meteorologist