Severe storms are expected to impact approximately 50 million people from the Southern Plains to New York on March 26, affecting parts of Illinois, Indiana, Ohio, Michigan, and Pennsylvania. The main threats include large hail, strong winds, and a few tornadoes. Storms are forecast to begin as supercells before organizing into a line, increasing the risk of widespread damaging winds. These storms are likely to develop late Thursday afternoon near southern Lake Michigan, before spreading east into Indiana and Ohio through the evening. Forecasters predict that supercells could produce large hail up to 2 to 3 inches in diameter, potentially producing several tornadoes, and potentially leading to heavy rainfall. The primary severe threat window is for Indiana, with severe weather expected to persist into the evening, but the severe threat is expected to diminish as storms move east and instability decreases.