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.

Another day of scattered heavy thunderstorms inside what forecasters called a juicy, "tropical-like" air mass Saturday has renewed the risk of flash flooding across several states from Iowa to Pennsy...