Thunderstorms will last through the evening, and then on Sunday, hot temperatures will return, with the heat index between 100 and 105 degrees. A flood watch is in effect as a threat of severe storms is expected by the afternoon for the Chicago area.

CHICAGO - Showers and thunderstorms are passing through the Chicago area on Friday afternoon, posing flash flooding risks. Additional storms will develop Friday evening and overnight, according to the National Weather Service. Torrential rain and flash flooding are possible.