If the precipitation starts off as snow on the lowlands... expect it to change over to rain or a rain and snow mix Christmas afternoon.
In addition to the possibility of snow on The Lowlands... strong winds will likely develop across the east wind prone areas such as Hoquiam... Enumclaw... North Bend... Buckley... and Orting on Christmas day. The east wind prone areas in the east Puget Sound lowlands or the Cascade foothills could experience localized gusts to 50 mph.
Historically... a white Christmas in the western Washington lowlands does not occur very often. Statistically... the probability of this happening is less than 10 percent. The last time there was a white Christmas in the lowlands was back in 2008.