After a nice Sunday with a pleasant lake breeze, Monday will be hot and humid with heat indices in the mid-upper 90s away from the Illinois lakeshore. Scattered thunderstorms are also possible in the area on Monday both during the morning and again during the mid-afternoon and evening hours with some storms carrying a localized flash flooding and gusty wind threat. The weather will remain hot, humid, and relatively unstable in the following days with a warm, moist air mass in place creating chances for scattered showers and storms each day. However, there will still be plenty of dry hours each day.
Monday: A chance of a few thunderstorms, mainly after 11am. Mostly cloudy, with a high near 89. Heat index values as high as 98.
Monday Night: Slight chance of thunderstorms. Mostly cloudy, with a low around 71.