This isn't something you see every spring - severe weather in the Pacific Northwest! A storm system is moving in from the ocean and bringing enough instability and moisture to help produce storms, some of which will be on the stronger side with gusty winds and hail the primary concerns.
Showers will build into the afternoon, with a few strong storms possible. Heavy rain could impact parts of the Cascades and Willamette Valley.
By Saturday night, cold air intrudes, and rain changes over to snow for the southern Oregon hills and mountains. Accumulations could top 6" for areas over 4k feet.
Temps will be warm to aid in storm development - highs in Boise will be 20° above average with that trend stretching into Montana and Wyoming! Enjoy the taste of June rather than mid-April!