AS far as PNW areas go, Baker almost always opens first and the early skiing there is among the most reliable in the country. In 3 out of the past 6 seasons, there was a good base. Last season they opened 100% of the terrain on the first day, with a base of more than 100".
On the other seasons, the conditions were marginal in 2 years and not open until december in 1. But the other PNW areas were in the same boat.
And Baker is too far off to be considered at all for the OP, unless you are absolutely determined and it's the only place open.
Alpental and White Pass are convenient to the drive from Seattle, but neither is a good bet for early season conditions.
Hood is the next most reliable, and easily the most convenient to the tri-cities of the cascade resorts. Fly into Portland, easy drive to Hood, down to Hood river and pick up the highway west. That should be your pick.
On the off-chance that Bluewood is open, I'd check it out. Close to the tri-cities, but so far from everywhere else, being in the tri-cities already would be your only chance to ski there.