There have been several times this season that the medium-range computer simulations have suggested bitterly cold air was on the way to the Middle Atlantic states in the 7-10 day forecast period.
And so they have again. This time, I am finally convinced. There is growing confidence that the first 2-4 days of next week will be the coldest of the season. The cold air has been building and growing across the Canadian Arctic, and the first surge has already moved into the central and western United States.
First things first…
Rain will continue through Wednesday morning. While there will be occasional breaks in the rain, it will be midday Wednesday before the rain finally shuts off and the sun emerges. A general 1-2 inches of rain will fall throughout our part of Virginia, but there will be some locations that get upwards of three inches of rain.
Despite the amount and duration of the rain, flooding is not expected. Maybe, maybe, the Dan River makes a run at bankful or edges out of its banks at the end of this week, but we do not expect enough rain to cause substantial problems.
Thursday through Sunday largely look dry and seasonable, with highs in the 40s and lows in the 20s.
Having said that, a moderate-sized storm is going to move through the Southeast Thursday into Friday. At this time, it is expected to hold in the Carolinas and Georgia, where it brings some cold rain. However, a small drift to the north would bring snow to Virginia.
Ironically, Southside Virginia runs the greatest snow risk with this system (late Thursday and Friday), but at this point, we would put the chance of accumulating snow from this system at just under 20%… and even lower in areas northward to Lynchburg. But if the forecast should suddenly change in the next day or two for late Thursday or Friday, you will know why. As it stands now, we are still forecasting a miss.
The Arctic air pushes in on Monday, and it will be cold, dry air, as highs probably hold in the 30s, even with the sun out. Lows may edge into the teens.
There are signals that a weak disturbance moves into the state from the northwest early that week, about Tuesday the 22nd: a quick-moving one nicknamed an Alberta Clipper. The air certainly looks cold enough to support snow, but how strong the disturbance would be is wide open to debate.
Historically, these systems do not provide much snow (less than an inch) for Central and Southside Virginia, unless the center passes just to our south as they move by. There is not much skill in forecasting the precise track of a system (which has yet to develop) 7-8 days in advance, but at this time, it appears to be the only other legitimate opportunity for snow in the next 2 weeks.
The day or two after that disturbance goes by will bring the worst of the cold. Still too early for specific high and low temperatures, but I would imagine highs on Wednesday (23rd) in the 20s, with lows in the single digits to lower teens.