Another cool night is expected tonight as winds become light under a clear sky. Temperatures are expected to drop into the middle to lower 30s across much of the region. Widespread frost is expected across southeast MO and south central IL tonight, with patchy frost expected across much of the remainder of the region. Monday will be the start of a rapid warm up as winds become southerly under a partly cloudy sky. Temperatures are expected near seasonal average in the lower to middle 70s across the region. (Please visit http://weather.gov/lsx for more information.)