It occasionally snows in Seattle, very occasionally.
It does not matter however, as soon as it snows 1/2 of a centimeter of snow, the roads go to complete shit because no one has any clue how to drive in 'snow' even if there is no 'snow' on the ground. There will be crashes galore, fucking over all the arterial routes.
In the insanely unlikely event that it decides to snow more then 12 inches, and that 12 inches decides to hang out for a couple days. There will be absolutely zero roads open, since there are a grand total of maybe three snowplows in western WA, non of which have seen preventive maintenance since 1974.
That said, if it does for some obscure reason does snow in seattle, please go hit up 'urban' as you will then be one less asshole trying to get all the 'pow' (pretty much a mix between water and slush) they think might be in the mountains.