Earlier today the National Weather Service issued a Winter Weather Advisory for much of western Washington due to the possibility for snow overnight in lowland areas.
While varying from area to area, the advisory says to expect 1 inch late tonight, then another 1 or 2 inches Sunday morning. Areas near sea level will receive little to no accumulation. Higher hills and inland areas may get up to three inches.
The advisory will be in effect from 10pm tonight, Saturday, to 10am Sunday.
Environment Canada has also issued a snowfall warning with similar expectations.