Snow maps are going to struggle on the boundary. Soundings and QPF are the way to go. I’m modestly happy with this run sitting on the western DC Beltway.
The column is holding on for dear life from 18 to 21z in the DC area. It eventually falls, but there’s almost 0.6” precip by 21z. Ratios would suck, but it would be a few inches of snow first in this scenario.
6" for December puts me only a few inches below normal on the year. As of December 10th I was still running last place over the past 10 years, but the three storms bumped me over 2016 and 2017.
DCA's ASOS is on the east (river) side of the runways. It is not near the buildings. Now, the snowfall measurement location is a completely different issue, but they seem to have fixed that in the past 5 years or so.
After driving down towards the river, I’m shocked that DCA did get on the board. There is no sign at all that it snowed, other than the cars that came in from higher elevations.