The National Weather Service has issued a Winter Storm Watch, in effect from 7 a.m. Thursday through 7 a.m. Friday.
A weather system will move from south to north over Western Washington during the day on Thursday and into Thursday night. With cold air already in place at the surface when the precipitation begins, it will likely begin as snow and change to rain. The change to rain will be earlier in the south and later in the north. It is expected that by Friday morning, the transition from snow to rain will have occurred everywhere.
Up to 12 hours of snowfall is possible at most locations, with snow accumulations of four inches or more possible. Travel will be greatly impacted, as roadway surface conditions may become slippery.