Snowfall totals have way over-achieved from Fredericksburg to southern Maryland: The image above are reports from the public and trained spotters as of this morning (image courtesy NWS: http://www.weather.gov/lwx/pnsmap?type=snow)
Here is what may be on the ground before the change over to freezing rain (Image courtesy NWS/Washington):
Total storm accumulations of 10″ are not out of the realm of reality in areas that have already received 5 to 7″.
The models are clearly under-estimating how potent the cold air was out ahead of this storm system. This worries me that our icing potential may be higher as a prolonged period of freezing rain could stack up to a quarter of an inch or more before the change-over to rain Tuesday morning.
DC Storms 
Agreed! Woke up this AM here in Chesapeake Beach to 4″ at 0830. It’s getting closer to 6″ as of this post. Heavy flakes with little to no wind.