UPDATE 7:45 AM: Winter storm watches have been issued generally west of Interstate 77 for the potential of 3 to 6 inches of snow on Wednesday. As a new low moves up the coast and some vigorous upper-level energy cuts into the back of the storm, some snow will likely wrap around the back side of the storm. This is something watch even farther east toward the Roanoke and New River valleys. (I expressed my doubts below, but some new data has me re-thinking. Be prepared for the possibility, at least.) Meanwhile, today, temperatures are slowly rising and will eventually go above freezing at almost all locations across our region, melting whatever ice formed this morning. But a raw day and night of cold rain, heavy at times, is on tap. END UPDATE
A mix of sleet, rain, freezing rain and snow is spreading across Southwest Virginia as Monday rolls into Tuesday. This is expected to continue off and on through the morning hours, but turn more and more to rain as temperatures aloft warm and those at the surface nudge above freezing. By afternoon and evening, periods of heavy but cold rain are expected to continue as a low-pressure system moves northeastward, inland but to our east. A few localized pockets may stay at the freezing mark and continue to collect ice long past when most other locations have warmed into the mid and upper 30s (“warmed” being very relative in this case). As a secondary low moves northeastward Wednesday, and a new Arctic cold front pushes in behind it, a period of snow may develop, with at least some light accumulations possible. The Roanoke and New River valleys and points eastward rarely get much snow off of a changeover from rain due to cold air advection (movement laterally over the ground, rather than developing from aloft via dynamic or evaporative cooling), so I have considerable doubts about whether this will develop, and many model runs have thrust a “dry slot” very near us late Wednesday. Still, we’ll keep an eye on how that develops, as there could be some upper-level support that changes the game and allows accumulating snow on Wednesday, especially west of I-81 (probably talking mostly 2 inches or less, with some locally higher amounts).
Feel free to share your observations in comments below (though they may not be approved for publication rapidly between about 1:30 and 5 a.m.)