National Weather Service United States Department of Commerce

There is a potential for light snow behind a passing cold front tomorrow. Most locations that do see snow will receive up to a dusting, but amounts up to 1" are possible within a narrow band. The highest chance of this occurring is in northeast MO and west-central IL.
A frigid airmass will settle into the region Wednesday night through Friday morning with lows ranging from the single digits to the teens. Highs Thursday range from the teens and 20s at most locations to the low-30s over southeast Missouri. Milder air returns Friday with many locations along and south of I-70 reaching well into the 30s. Southeast Missouri will feel the low to mid-40s!
A weak winter system moved through the region Tuesday morning through late Tuesday evening, bringing brief, localized periods of heavy snow. Snowfall rate of up to 1.5" occurred at St. Louis Lambert International Airport around noon with several instances of rates near 1" per hour and 1/4 mile visibility. Most locations reported 1-3" of snowfall with a slightly more or less by location.