Downbursts occur when cool air plunges earthward out of thunderstorms, often during driving downpours. Once making contact with the ground, the powerful winds fan out in all directions, setting up the powerful straight-line winds so many of us associate with t-storms. Winds hit 60 m.p.h. in the Loop in a downburst late Thursday. It was captured by WGN time-lapse cameras on the Hancock Building. The footage is posted on the wgntv.com website.
Winds reached 74 m.p.h. as they roared offshore at the Harrison-Dever Crib just off the Chicago shoreline. Other thunderstorm wind gusts late Thursday reached 72 m.p.h. at Midlothian. The storms bombarded parts of Joliet with golfball size hail (1.75” in diameter). During the evening, the t-storms spread east into Indiana and Michigan, where a late night tornado (9:25 p.m.) south of South Bend seriously damaged homes and caused injuries.
--By Tom Skilling, WGN-TV Chief Meteorologist
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
