A trough of low pressure in the upper levels of the atmosphere will be responsible for bringing a brief period of unsettled weather to the Northwest. Unfortunately, it will coincide with this weekend. On Friday, rain showers will begin to move into the Pacific Northwest coast during the afternoon and evening hours. These showers will be light, but winds will begin to pick up. At times this weekend, winds will gust up to 30-40 mph, especially east of the Cascades.
Then on Saturday, the activity will become widespread as rounds of rain move into much of Washington and Oregon as well as northern portions of California, Idaho, and western Montana. There may even be some light snow that may accumulate a few inches at the very peaks of the Cascades thanks to the below-freezing air temperatures aloft.
By Sunday, a few rain showers will continue along the coast, while showers are a bit more widespread across northern Idaho and western Montana. Snow will also be possible in parts of the northern Rocky Mountains, which may also amount to a few inches. Light snow will also persist across portions fo the Cascades. This comes as significantly-below average temperatures move in at the surface. Widespread temperatures of 15 to 30 degrees will be commonplace throughout the region on both Sunday and Monday.
On Monday it will be cool, but most of the precipitation activity will dissipate other than a few lingering rain and snow showers at the coast and the northern Rocky Mountains.
By Tuesday, the region will dry out completely as above average temperatures surge back in from the south.