"Atmospheric river" will pour over Pacific Northwest through Friday
There’s a potential for river flooding Thursday through Saturday along creeks and rivers in Northwest Oregon and Southwest Washington.
And, there’s a potential for debris flows near the Lionshead, Beachie Creek, and Riverside burn areas.
And, landslides are possible near steep terrain.
Periods of moderate to heavy rain will begin Wednesday night as a warm front moves in. This will continue through Friday, as an "atmospheric river" pushes into the region. Snow levels will be high during this rain event, generally above 9,000 feet.
The National Weather Service reports that total rain amounts Wednesday through Friday night may exceed 6 to 12 inches in the south Washington Cascades, north Oregon Cascades, north Coast Range, and Willapa Hills. 1 to 3 inches of rain is possible for the interior lowlands, and 2 to 5 inches along the coast. Rain amounts this high may be sufficient to cause flooding of creeks and rivers in Southwest Washington and Northwest Oregon, especially creeks and rivers draining the north Coast Range and Cascades. At this time, the best chance for river flooding appears to be along the Grays River near Roseburg, the Wilson River near Tillamook, the Trask River near Tillamook, and the Nehalem River near Foss. Creeks and smaller rivers in the Willamette and coastal
tributaries may also be impacted.