Much colder temperatures and a chance of spotty lowland snow at times Wednesday night through the weekend. Low temperatures Thursday morning will generally be in the low 30s but highs will struggle to reach 40 during the afternoon hours.
Weak Fraser outflow along with a gradually drying air mass will allow temperatures to fall even further Friday and Saturday.
Highs will remain in the 30s with low temperatures down in the 20s. All of western Whatcom and Skagit counties and some other cold pocket locations could see temperatures fall into the lower to mid teens overnight. Only a slight moderation is expected Sunday. Temperatures will slowly return to near average early next week.
There is still moisture in place over western Washington which will result in scattered showers through Thursday morning. The air mass will become cold enough later Wednesday night so that some showers may fall as a mix of rain and snow or possibly just snow down to sea level. Isolated snow amounts across the area will likely remain below one inch in this type of pattern.
However... the Puget Sound convergence zone is expected to be active Wednesday night through at least Thursday which may produce locally higher accumulations.
Areas most likely to get convergence zone snow will be from north Seattle along the I-5 corridor to Bellingham. Some places could get 1 to 2 inches of snow late tonight through Thursday afternoon.
Drier air will filter into the area Thursday night so the threat of precipitation will greatly diminish through Friday. Another system may arrive sometime Saturday and Saturday night. Current computer models suggest there is a chance of some light accumulations across western Washington with this system.