My meteorological colleague Rick DiMaio shares this revealing shot from North Lakeshore Drive of the ominous "shelf cloud" with Wednesday evening's powerful thunderstorm cluster. The storms produced damage and local 40-50 m.p.h. wind gusts over a broad area of Chicago's north and far northwest suburban area—but, interestingly, peak velocities of 25 m.p.h. at O'Hare International and 18 m.p.h. at Midway Airport. The rush of cold air out of the leading edge of a thunderstorm like Wednesday's cools air ahead of the cloud to condensation producing the rolling shelf cloud in the process.
Thanks Rick for the spectacular shot!
Tom Skilling
Photo courtesy: Rick DiMaio
