Powerful thunderstorms sweeping Chicago area a second day
Powerful eastbound thunderstorms are pounding the same areas west and north of Chicago Tuesday hit hard by thundery rains yesterday. The storms are headed toward Chicago. Powerful wind gusts accompany the 55,000 ft. tall thunderstorms and are sending temperatures plummeting. Readings beneath these storms have dropped nearly 20-degrees--from pre-storm mid 80s to mid to upper 60s once the rains commence and strong winds hit. Gusts of 43 mph have swept Waukegan as of 4:10 pm and 39 mph gusts have been clocked by WeatherBug sensors in DeKalb where another 0.65". Our live cameras there indicate visibility has dropped to zero in the downpours. The same is true near the Illinois/Wisconsin border at Algonquin.
The humid atmosphere is in an explosive state again as a cold front races across the area. Dangerous lightning accompanies the storms. Nearly 1900 cloud to ground strokes have been recorded in just the past 10 minutes (as of 4:15 pm) within a 225 mile radius of Chicago.
The latest squall line is much narrower than Monday's suggesting the storms will hit hard, last an hour then depart. A severe thunderstorm watch is in effect until 9pm this evening and indications are the last of these storms will depart Chicago's northwest Indiana suburbs before midnight. The cold front behind these storms promises relief from the heat and humidity the remainder of the week--though a few thunderstorms can't be ruled out later Thursday and later Saturday.
Of great interest here are continuing indications a lobe of hot air of the vast western hot air mass is headed toward the Midwest next week. We plan more coverage of that on our television weather programs and here on our weather blog later this evening and on our Chicago Tribune weather page at the back of the Metro Section Wednesday.
Tom Skilling
Chief Meteorologist
WGN-TV