Barring a few very strong fronts, the weather in the Puget Sound region is quite difficult to predict. Heck... you can check a few different news stations and none of them agree as to the forecast. Yes, it will be wet. How wet is up for grabs.
Tomorrow can be pretty accurate ''overall', yet the forecasters can claim temps that are 10 deg different. Our region is unique in the country and has a habit of creating anomalies for predicting the weather. I know of weather stations at Boeing field (maybe 50' above sea level), and SeaTac (about 450').
They are about 10 miles apart and the weather can be quite different. I've driven to werk in the snow, and seen what I can only describe as a wall in the snowfall. It's snowing on the freeway where I'm at, and 20 ft away it's raining. Very odd...
I just check a couple stations, average them, and look out the window. Works every time.