Observation notes: in my back yard in Boise, Id. Could be a European Yellow Underwing also. It's about 1 1/4"- 1 1/2" or so long, wing span 2" or so. Compares very close to the pic of Greater Red Dart in your Image Gallery
Verified by: Robert Martin
Verified date: July 11, 2016
Coordinator notes: I documented this species in Helena, MT. The "Moth Photographers Group" range map shows this species occurring in western Washington and Oregon. Your siting is a nice connector of those previous documentations.