A series of strong to severe thunderstorms moved southeastward from southern Wisconsin into northern Illinois and northwest Indiana starting on August 16, 2025. These storms brought damaging winds, large hail, and torrential rain, primarily affecting the Chicago metropolitan area and surrounding suburbs. The National Weather Service (NWS) Chicago office highlighted that the primary threat zones shifted throughout the afternoon and evening, with clusters of storms continuing into the night and early morning hours of August 17. Heavy rainfall from these storms caused flash flooding in parts of Chicago, including Cicero, and structural damage such as a roof being ripped off an apartment building in Mount Prospect. Additional rounds of storms were expected to continue through Monday and Monday night, with heavy rainfall posing the main risk and localized flash flooding possible. While widespread flooding was not anticipated, river rises were expected in the hardest-hit basins. The stormy pattern was forecasted to persist through midweek with warm and humid conditions before cooler, less humid weather returns later in the week.