During the next 48-h, a few weak troughs in westerly flow will move through (see upper level--500 hPa--chart for Friday afternoon). The result will be fairly substantial precipitation over the
mountains during the period, with lesser values over the western lowlands (and even less east of the Cascade crest). Take a look at the 48-h precipitation ending 5 PM on Saturday. 2-5 inches over the western slopes of the Cascades, but little along the eastern slopes of the Cascades. Snow in the higher passes. Also notice that Kitsap is relatively dry...the result of descent off the Olympics.
Sunday is the transition day--the beginning of the drying and warming. By Monday morning, the upper trough is way to our east and substantial ridging has developed over the eastern Pacific (see map). Get your sunglasses! Stock up on plants and fertilizer.
The ridge strengthens further by 5 PM on Thursday (see below). You don't need to be a meteorologist to know what this means.
And if that is not exciting enough, take a look at the 8-14 day temperature forecast from the Climate Prediction Center. High probability of above normal temperatures over the entire western U.S.