As predicted, cold, continental air is entrenched over the Northwest (see surface forecast for 10 AM Friday of sea level pressure and low-level temperatures). We are shielded from the coldest air (purple color) in the mid continent by the Rockies and Cascades.
The latest NOAA snow analysis shown plenty of lowland snow include Whatcom County and Vancouver BC, and from Olympia to Salem.
Today (Friday) will see high temperatures only reaching around freezing and Saturday morning will again slip into the 20s and teens. But change is coming. Saturday will be generally dry (perhaps a few errant flurries at most), but Sunday morning a Pacific weather system will approach. With cold air in place, it will start as snow in many areas of western WA. Here is the predicted snow cover percentile for western WA at 10 AM Sunday...even Seattle gets some.
Snow depths are not impressive over the lowlands.
By late Sunday/early Monday the warmer Pacific air will be in place and the normal wet/mild weather we so love will return.