The heaviest rain to hit the city’s South Side in four years began modestly Thursday in the midst of the evening rush hour. Sprinkles started falling across the area just after 5 p.m. But within two hours a full scale deluge was underway. Repetitive downpour-generating t-storms were to sweep southwestward over a narrow 20 mile wide corridor extending south from the Eisenhower Expressway westward into northern Will County. Strengthening NE winds appeared to provoke the rainy atmospheric set-up which unleashed 2.28" of rain on Midway Airport in just 78 minutes. A process known as “speed convergence” contributed to the area’s latest cloudburst. Strong NE winds off the low-friction environment of Lake Michigan converged once onshore with lighter winds slowed by friction produced by the land. Towering thunderstorms resulted halting the Sox game and flooding the Archer/63rd street intersection.
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
