From Portland National Weather Service: Significant rainfall beginning tonight and continuing through Saturday over SW Washington and NW Oregon.
A mild and very wet front will stall over SW Washington and NW Oregon tonight through Friday night. The front will lift North and West Friday night with rains continuing but at weaker rates. The primary rain band will then shift south and east as a cold front across the rest of the area Saturday afternoon and evening.
Additionally, breezy winds will continue to strip leaves off trees which may result in clogged storm drains and culverts. This may lead to ponding of water on roads and localizes flooding.