Saturday will be a chilly and cloudy. Rain showers will be possible late in the day as a weak weather system arrives. No doubt about cold air arriving Saturday night. Modified arctic air will arrive from the north. Temperature Sunday morning will be in the 20s. Moisture will be limited but I think it's possible a few flurries will fall Sunday. No accumulation in Portland or the valley but the mountains may get an inch or two.
Temperatures begin to moderate Monday and Tuesday Oregon liquid sunshine will be possible.