Chicago is under a severe weather alert as the National Weather Service forecasts potential tornadoes and large hail, particularly south of I-80. The day started with a temperature drop, signaling the arrival of a storm system expected to bring rain and stormy conditions throughout the day, with the most severe weather anticipated in the afternoon and evening. The weather service has issued warnings for severe thunderstorms that could bring damaging winds up to 70 mph, large hail, and the risk of tornadoes. Residents are advised to stay informed through reliable sources like the National Weather Service and local news, and to take necessary precautions for their safety.