Updates: Precipitation has switched to icy mess after coating to couple inches of snow.

Wintry mix and rain expected into tonight. Precipitation may change back to snow before ending.

2:25 p.m. update: The rain-snow line has pushed into northern Montgomery and Loudoun counties as the initial snow phase of this storm wraps up and transitions into more of an icy rain. The exception is likely to be west of Frederick, Md., and especially the Interstate 81 corridor, where precipitation may remain mostly snow, mixing with sleet at times.

Before the changeover, Reagan National reported just a trace of snow, while Baltimore-Washington Marshall Airport tallied 0.5 inches and Dulles 2.1 inches. In Leesburg, a social media report indicated about 3 inches had fallen but precipitation was turning to sleet there.

https://www.washingtonpost.com/weather/2020/12/16/dc-area-forecast-snow-sleet-arriving-late-morning-changing-heavy-rain-this-afternoon-then-back-snow-tonight/?