Dew Point (dp sat morning image) forecast for early Saturday morning, Dec 20.  If skies clear, surface temps can fall to or near dew point.  Model progs dp temps ranging from 5 F to 15 F OR north to WA.

Air at approx 5,000 ft (850 mb image) forecast to range from 16 F in southern OR to a very cold -15 F over Lynden.