Rain showers are moving onto the coast now and move inland by late evening. There will be some rain continuing most of the night Thursday into Friday morning, with some breaks here and there. This rainfall will be light to moderate, but bring some nice wetting rains to the area to start Friday.
This will be the leading edge of an unusual “atmospheric river” bringing a stream of rich moisture across the Pacific right into Western Washington. This is a fairly common feature in our fall weather but happens this time of year perhaps one in a decade. The last time we had an inch or more in the first part of August in Seattle (through Aug. 16) was indeed ten years ago — in 2015.
And as compared to fall or winter atmospheric rivers which can cause all kinds of problems like flooding and landslides, this one will be almost entirely beneficial to the area. Soils are ready to gulp up water and low river levels mean water rises will be of little consequence…