Thunderstorms mixed with heat and humidity move into Chicago area

Temperatures and humidity are rising in Chicago with a chance for thunderstorms to roll into the region Sunday evening and into Monday. National Weather Service forecasters say "periods of thunderstorms" are possible Sunday and Monday night, but the exact timing and location are uncertain. Hot and humid conditions for Chicago are more of a sure thing, according to the weather service, with temperatures hitting 91 and the heat index pushing 105 for Sunday. Monday's temperatures are expected to…