A moderately strong atmospheric river will impact western Washington Friday through Saturday night, bringing moderate to heavy rainfall to the region. Mean rainfall forecast remains between 2 to 4 inches with locally 5+ inches, with the heaviest rain on track to fall over the Olympic Peninsula and over the northern and central Washington Cascades. While the Skokomish River is the only river currently forecast to enter minor flood stage on Saturday, many other rivers are forecast to reach action stage on Saturday, including the Bogachiel River on the Olympic Peninsula and the Skagit, Snohomish, Skykomish, and Snoqualmie Rivers in the Cascades. Some uncertainty remains over rainfall amounts over the mountains, and river conditions will continue to be closely monitored.
Where heavy rain occurs, the relatively high rain rates could produce flash flooding/debris flows on the more sensitive burn scars. It could also cause ponding or nuisance flooding in urban areas and small streams where drainage is poor or drains are clogged by leaves.