Watch the warmth fade away on the GEFS:
Long range 500mb height anomalies depict a strong trough in the east:
The deep snowpack in the NW at hour 192 argues for an air mass that is continuing to get colder and when it is triggered to come eastwards will be very cold.
Indicies support this change with a tank in the ao and nao:
PNA still negative so expect cold centered in the east but trough nationwide with widespread cold across southern canada and an active storm track. An alaskan ridge will pump and hold allowing this frigid air mass to move eastwards. The pattern change is coming and in a big way without any stratospheric support. As stratosphere continues to warm through december a sudden warming event may occur(favoured in an east QBO year) which would lock in a cold january.