Light snow has been observed at Bellingham, Shelton, Olympia, Chehalis, Vancouver (WA), and Portland. The most snow apparent on regional cams is around Vancouver, WA:
The culprit: a weak disturbance moving southward down the coast and relatively cool air over the interior.
The latest radar shows the precipitation pattern. On the coast, the precipitation is rain, and the interior stuff is quite light. Seattle should stay dry, as should eastern Washington. We do not have super cold air over us, but evaporative cooling is allowing the snow level to drop to the surface in some locations.