In spite of light rain and temperatures in the 60s Sunday, sleet and snow follow Monday.
The cold air is not that far… notice the temperatures in Northern Virginia early this evening.
While there have been shades of a system of this magnitude in the computer simulations for several days, it has only been in the last 48 hours that the shorter range simulations have locked on the precise timing of the precipitation and its interaction with sub-freezing air. Most of the 3+ day simulations had been inconsistent in placement of the heavy precipitation shield and the timing of the cold air arrival.
Arguably, there had been a trend in some of those simulations southward with the precipitation, but I was still quite skeptical, especially because the center of the storm did not reach the California coast until Friday.
Overnight, there will be occasional rain across the southern piedmont of Virginia and the adjacent mountains to the west.
A few hours before daybreak, winds will turn from the northeast, and sub-freezing air will begin to drain into these locations. The result will be a changeover to sleet and then snow before all precipitation ends by around dusk. Most accumulating precipitation should be over by around 4pm Monday.
For Greater Lynchburg (including Amherst, Appomattox, Bedford, and Campbell Counties)… expect the rain to change over sleet an hour or so before daybreak. There will be the distinct pinging sound of the sleet for 2-3 hours before a change to snow. Snow will continue for about another 4-6 hours, and it will come down heavily for at least a couple of those hours.
As much as an inch of sleet before the changeover, with 3-6 inches of snow on top of it. If the cold air can get in a little faster, 4-8 inches of snow will be more common. But it is difficult to imagine less than 3 inches of a sleet/snow mess on the ground before the day ends.
For Southside Virgnia (including Danville and Martinsville… plus Charlotte, Halifax, Henry, and Pittsylvania Counties), probably still raining at daybreak, but the transition to sleet occurs an hour or so afterwards. Sleet lasts through late morning, with an inch likely before a transition to snow, as a result, the snow amounts will be decidedly lower. I like the idea of 1-3″ of a sleet/snow mix on the ground by the time it all ends, but there is an outside chance at squeezing out 2-5″.
For areas Northward (including Albermarle, Bath, Botetourt, Nelson, Rockbridge Counties), the changeover to snow is earlier, and it appears that the ribbon of highest precipitation will lie in these areas as well. Conservatively, 4-8″ of snow will be common here, with some areas getting into the neighborhood of 10″ in this zone… probably somewhere in Albermarle or Nelson County… and there very well may be a sweet spot that can get 12-14″ in this area. At that point, it is about snowfall rates.
Southwestern areas (including the Roanoke and New River Valley), the amount of precipitation will be a little lower and the colder air will be a little slower in arriving (the sub-freezing air at the surface is coming from the northeast). Rain transitions to sleet shortly after daybreak, then to all snow (north to south) during the morning. A wider range of accumulations here, with amounts running 2-5″ toward the Roanoke Valley, westward into Giles County, but dropping to 1-3″ farther south toward Carroll County. More specifically, for Blacksburg, Christiansburg, and Radford, I like 2-4 inches.
Not to be lost will be the dramatic temperature drop from Sunday afternoon. Temperatures by daybreak Tuesday will be 8-14 degrees.
There are also large-scale systems upstream that will be nearby this Friday (March 7) and later next week (March 11-12). Still time to monitor, as all options are still on the table for these two storms.