A strong cold front will move through Missouri and Illinois today, bringing a much colder air mass into the region. Rain is expected to develop late this afternoon and spread northward, gradually changing to a wintry mix of sleet, snow, and freezing rain as it encounters the colder air near the surface. Thunderstorms are also possible, especially over southeast Missouri and southern Illinois. Precipitation will end late tonight and early tomorrow morning.   (Please visit http://weather.gov/lsx for more information.)