Rain will develop before rush hour on Tuesday across the Washington Region with a quick transition over to heavy, wet snow across the foothills of the Blue Ridge mountains, Shenandoah Valley and northern Maryland. The model animation below is from the high-resolution Canadian model which has come into alignment with the European forecast model. The animation shows rain developing at 07Z (3AM) and quickly changing over to Snow through the mid-morning hours west of the immediate metropolitan area. The animation ends at 4PM when a moderate to heavy mix of rain and snow may be setting up right across the interstate 95 corridor. Those of you commuting to the northern and western suburbs on Tuesday afternoon should plan for conditions to deteriorate, especially on secondary, untreated roadways as temperatures cool into the lower 30s.