The image above from the latest High Resolution Rapid Refresh (HRRR) model shows just how much moisture this storm system has to work with as heavy snow breaks out across southwestern Virginia (dark blue colors) this evening (image runs through 7pm this evening).
Classic Cold Air Damming Event Setting Up:
The models have held on to the idea that colder surface temperatures will be hard to scour out on Wednesday, suggesting a classic Cold Air Damming (CAD) event is setting up east of the Appalachians and Blue Ridge.
While the timing of when the Snow on Wednesday morning will change to Sleet and Freezing Rain Wednesday afternoon is still in question, a strong subtropical jet stream and Gulf moisture will aid in very heavy precipitation rates meaning the Snow, when it gets going on Wednesday morning will be coming down at rates of 1 to 2″ per hour!
The trickiest part of the forecast is how long does Sleet (frozen rain drops) hold on before Freezing Rain (rain that falls as liquid and freezes on contact) takes over? If Freezing Rain ends up being the predominant precipitation type for a large portion of Wednesday afternoon through the late evening, there could be thousands without power from interstate 95, points west… something to watch very closely. I hate Freezing Rain so I’m hopeful Sleet holds on as long as possible.
Latest North American Model (NAM) showing Future-Cast Radar Simulation through 1am (06z) Thursday.
Updated Snow Map: Click on image for larger view
Updated Ice Map: Click on image for larger view