Summary:

High pressure remains anchored off the coast acting as a storm shield.  The high will shift West slightly by midweek allowing a cold front to drop down the West Coast bringing a shot of cold and some light snow.  Then the high pressure ridge shifts back to just off the coast until the New Year.

Details:

Temperatures in the 40's will drop into the 20's Thursday behind the front.  Models are in pretty good agreement on 1-3 inches of snow on the mountains with the front Thursday.  The ridge is not expected to shift up into the Gulf of Alaska anymore so the cold shot will be short-lived.  

The ridge will shift right back off the coast Friday warming temps back into the 40's by next weekend.  The storm track will be kept to the North from Oregon up into Western Canada.  The best snows will fall from Mt. Hood northward.  Week 2 some of the model runs amplify the ridge further up the West Coast pushing the storm track well up into Canada.

There is finally a sign of a change around the new year.  The GFS is hinting at the ridge off the coast blocking the storms shifting North into Alaska, and the European ensemble runs have the ridge shifting North into Western Canada.  Both have a decent size storm approaching the West Coast by New Year's eve as the storm door opens.  Hopefully this trend continues.  The pattern they are showing is the pattern the CFS has been forecasting for January with the blocking high in Alaska and Western Canada and storm track underneath into the West Coast.

Let's hope there is a pattern shift to start the new year, and a much wetter pattern for 2014...BA