UPDATE 7:30 AM: Several reports of 3-5 inches are coming in along a strip from northwest of Blacksburg near Newport, throughCraig County, across the Roanoke Valley, and surrounding parts of southern Botetourt and western Bedford County. Amounts were less with rain/sleet mixing to the south and east, and less to the north with more limited moisture. Temperatures, already slightly above freezing, will pop several degrees above freezing by mid to late morning, and may even challenge 50 with some sunshine today, so roads should clear fast. As the big low tightens up off the Northeast coast giving that region a historic blizzard, we’ll get gusty winds topping 40 mph by late afternoon and evening. END UPDATE
The quirky winter of 2012-13 is writing another odd chapter on this Feb. 7-8 that will be long remembered by Roanoke Valley snow fans as a rare time that they got more snow than most locations that usually get more snow in Southwest Virginia. Snowfall amounts by morning will likely top 3 inches at many locations in and around the Roanoke Valley — the higher elevations just west and southwest from Catawba to Bent Mountain likely getting just a little more than the valley itself, and some areas just to the north and west in Botetourt County, too. Officially at midnight, Roanoke had 2 inches (WDBJ) with snow still falling, while the National Weather Service office at Blacksburg only had 0.3 inch of mostly sleet. It will likely be many moons before Roanoke has an official sixfold snowfall advantage over Blacksburg at any point in a winter weather event (amounts vary quite a bit in the New River Valley, though — and early morning snow is pushing amounts a little higher, with already another 0.2 inch of snow reported at Blacksburg as of 1:15 a.m.).
Why did this happen? Over the Roanoke Valley and surrounding areas, a weak cold air wedge and evaporational cooling from falling precipitation into somewhat drier air were just enough to overcome a slight push of milder air aloft from the south. The “warm nose” won out to one degree or another (literally 1 degree in some cases) almost everywhere else, leading to more mix, primarily sleet, or even rain/freezing rain at most locations to the south, east and even west and southwest.
The low-pressure system that brought the wintry weather to Southwest Virginia will join forces with a northern-stream low crossing the Ohio Valley and Great Lakes to produce what looks to be a historic blizzard in the Northeast later today into Saturday. We’ll get some breezes off that tightening low, but highs should still make at least the 40s today, even where there is new snow and sleet cover.