The severe weather poses risks to millions across the Midwest and Northeast. On Wednesday, more than 35 million people, including those in Milwaukee and Chicago, are under a Level 3 severe thunderstorm risk. Hazards include large hail, tornadoes, and wind gusts up to 75 mph. Flash flooding is a concern, particularly in areas experiencing repeated storms, with localized rainfall totals exceeding 2 to 3 inches. By Thursday, the threat expands to include over 125 million people in the Ohio Valley and Northeast, with all severe weather hazards possible. Urban areas and regions with poor drainage are especially vulnerable to flooding.