Imagine it happens and we have a white Christmas. Wonder what we would need to see in the models for that to change

No doubt. The low of 5 at OLM on 2/25/11, the latest they've been that cold by an almost three week margin, is right there behind Dec 2013 at EUG for the most impressive surface cold anomaly of the 21st century in the PNW. The whole 2008-2014 period was pretty blocky in general.

PDX-EUG -5.6, PDX-MFR -12.9 good for 40-45+mph gusts

Perhaps I should take a bite of the 2017 Christmas snowball for good luck!

Definite spike in snowfall around Christmas Eve and Christmas day on the terrain bleed-y GEFS