Here are my thoughts on December. I still feel okay about this, through it may end up being a bit warmer then I thought.
December 2021 Outlook
December Analogs: 2007, 2000 (x2), 1974, 1970, 1995, 2005 (x2), 2017 (x2), 2008, 1983, 2020
The polar vortex should take some assaults throughout the latter portion of November and much of December, however, it should remain intact and ultimately intensify and consolidate beyond the New Year and later in January. This is consistent with basin-wide, mixed-type la nina events. The month should be active with a multitude of moderate snowfalls for the northeast, with the most significant event likely to occur the week of Christmas between the 19th and 26th. A white Christmas is highly likely for the majority of the region and a storm on the holiday itself is a distinct plausibility. Plan accordingly. Although the focus will be on the northeast via a mix of Miller B systems and southwest flow events whenever blocking relaxes, the mid atlantic should receive some snowfall due to a subtle subtropical influx coupled with a variable PNA.
The month should not be exceedingly frigid, as the very mild fall has ensured a late developing cold reservoir. Anywhere from near normal close to the coast to as much -2 departures well inland should cover the monthly departures
The thing to watch this month is whether we can get the lower heights flushed out of AK this month. If we can, I think we are right on track for a decent season....if we do not, then that spells trouble IMO.
Hopefully someone can post the latest guidance...