That was a fun storm to track, and reminded me a lot of the February 2011 event in regards to the really tight northern gradient of precipitation. Looking back at my forecast map I put out, there were two things that I mentioned could go wrong with the storm.
1) "The biggest bust potential with this system is how sharp the precipitation gradient is on the northern side of the storm. Minor shifts in track will nudge the totals either north or south a bit."
2) "I know a lot of models are showing more significant snows for central/se VA, so my map is a bit on the low side. The gfs and nam are both showing a bit more for central VA/Richmond area, but I think this is a little bit overdone due to the warmer ground surface temperatures at onset."
I decided to keep snowfall totals up across the central and northern Valley, east across the Blue Ridge to DC and Fredericksburg because I believed the storm would track a a bit further north than modeled, throwing the northern extent of precipitation into NOVA. Well, it did end up tracking farther north. 00z models had taken the low off the coast of central/southern South Carolina before swinging it northeast and out to sea. Taking a look at the 7pm storm prediction center analysis yesterday, the low was clearly farther north (much closer to the North Carolina/South Carolina border.
Even the water vapor imagery looked impressive. This looks like a significant winter storm for all of Virginia.
Precipitation was shot as far north as the Mason-Dixon line, but a layer of dry air aloft prevented it from reaching the ground. Basically areas north of I64 ended up with 6-8 hours of virga storm. Here's an image I posted at 3:45pm showing exactly where this line was setting up.
Radar imagery was showing some decent dbzs working their way farther and farther north, so I figured that at least areas just north of this line would eventually saturate and get snow all the way to the surface. Instead, northerly winds held strong, locking in the dry air. Higher elevations of the Blue Ridge still saw flakes fly since the dry layer between clouds and ground wasn't as thick. These sharp gradient events always come down to a matter of 20-30 miles.
The 2nd tough part of the forecast was how quickly cold air would work into eastern areas. Models had been painting widespread 4-8" across much of central VA including the greater Richmond metro. My forecast was on the low side since I figured cold air would struggle to work through, and once it did...recent warm temperatures and rains would limit accumulations a bit at the onset. This did end up being the case. Most of central VA was in the mid to upper 40s around lunchtime, and didnt drop into the 30s until later in the afternoon. Once snow started falling, it did fall with a vengeance, providing anywhere from 1-3" (isolated locations up to 4"). Without a cloud in the sky today, satellite imagery clearly shows current snow on the ground.
Overall, the worst part of my forecast was the northern sector due to the dry air. There was also a bit of a snow hold along the eastern side of the mountains where downsloping often both dries and warms the air. The sweet spot of my forecast map was pretty good, although some areas saw more than the "locally 10 inches" that my map had. There were several reports of upwards of a foot. Below is my final call map and the actual amounts.
The highest amounts reported from each state with this system:
West Virginia: Princeton (15")
North Carolina: Creston (14")
Virginia: McClure (13.5")
Kentucky: Clover (6.3")
Tennessee: Johnson City (5")
Alabama: Cullman (4")
Mississippi: Ackerman (4")
Massachusetts: West Harwich (4")
For a full list of snowfall reports...go to http://www.wrh.noaa.gov/sgx/kml/lsr.php?cwa=rnk&lsr=All