The first accumulating snow of the season is possible tomorrow with a strong cold front moving south today. Behind this front, cold air and moisture increase overnight tonight, bringing rain and snow. Overnight precipitation stays as rain through 6 AM. Snow will begin as early as 7 AM on Monday for our northern counties. St. Louis metro will likely see rain ongoing for the morning commute. With the freezing line shifting south later in the morning, the bands of snow will shift south as well. St. Louis metro will see snow by roughly 10 AM to noon. Ongoing light snow showers are likely through the afternoon and exit to the southeast through the early evening.
Light accumulation is possible, however, any accumulation on the roads is unlikely. Grassy surfaces and elevated areas could see up to 1" of snow. Areas north of I-70 may see over 1". Highest totals look up to 1.5" - 2". This will not cause major problems, but it will likely be a slow go through the day. Allow extra time as you hit the roads. Any rain or snow always makes for slow driving conditions!
Behind this, we settle into cold, arctic air. Temperatures will be in the teens and 20s into Tuesday. Bundle up!