I still remember the radar lifting the heavy snow up into Maine before hitting the brakes and ripping back south as an awesome band of 3"/hr fluff with thunder. One of the cooler radar loops I can remember and easily the greatest winter landscape of my life. In fact my avatar picture is from that morning.
Looks like 2.5" with heavy snow continuing. Sleet approaching, but surface temperature has not budged from 21 all day. A glaze to cap everything tonight seems likely. Looks like we've clawed our way over the one foot mark on the season.
Even if you could observe the atmosphere and model it at the atomic level, there would be a certain amount of Brownian randomness that is fundamental to physics and ultimately expressed at the classical level as error bars in the forecast.
You're in the HV and were able to easily tap into that funneled arctic air. Most of us started around 30 and then plunged as the air drained south. This is much colder to start for most of our forum.
Man, I tell ya, I'm at 10" this year and about 3" in actual winter. This is like a slightly below average year in DC. Those sons of guns must be real gluttons for punishment. I couldn't take this on a regular basis.