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Good thread. Seems Ural high and especially the +EAMT may weaken the vortex. Seems mid December is the tipping point to see if, and how, this goes down. Will it be enough, and will the vortex cooperate is the question. Tonight's Euro extended range will be very interesting, as Simon mentioned.

The call for a - EPO during mid December is gaining some traction on the long range models.

Don't get sucked in. Ha ha. Glad to see you posting. How you find the time is a mystery. I know your busy. We are dealing with some things that normally don't exist. or should I say coexist.

Not every day. 588 jeez

Damn the AO forecast looks good. Hope it happens !

A lot going for early December , especially towards the second week of December. Including a possible PV displacement, PV elongation, and the effect of a Siberian warming and the 7 day lag to NA, especially in the East. The displacement event if it were to occur could have implications for later in the month, in a way echoing Matt's thoughts from the post above.

Interesting to keep track of during mid to late December for any sensible weather implications in January.

Would be awesome if the actual blocking turns out more robust and longer lasting. I would love a December 09 event this way And to make it even better................. to happen near Christmas.

Extreme + PNA on the way it appears. Euro supports it as well. Question is the eventual evolution in early to mid December. Inland snow then a more significant event somewhere in the East.

Yes, that is true. Several mets and pros have mentioned a period in December when the NAO may drop. There is also a huge wave breaking event getting under way as well in the North Atlantic. This may have implications in the NAM domain as well . As mentioned here by Simon:

Interesting change today, with the caveat needing to see consistency in the next week, however, a nice drop forecasted in the AO domain.

Would love to eventually evolve the pattern change to a possible - EPO as HM mentioned recently moving deeper into December.

Exactly, anyone thinking snow in early December with a well above average source region is grasping for straws. As CAPE mentioned maybe the real deal, if we ever get one, is when Canada chills down through cross polar flow / - EPO later in the month of December, or beyond. Not sure I agree with Eric Webb about the South getting snow in the depicted pattern outside of the higher elevations. There was always some hope December may deliver by being a shoulder month with a less strong PV. ( But, hey it really is strong currently so... ) Also, there are signs zonal winds may decline later in December. This may assist with HL with blocking, along with a couple other factors.

As expected the weeklies have some major changes. ( for the better )

As we exit November and head into early December. I like !

A few things set in motion during the next week or so...... impact early to mid December for us.

When Anthony is interested you can't help but to be more hopeful. At least a December torch seems unlikely at this point, well at least until the 22 nd.

Some continuing signs this morning that we might be able to achieve a more blocked regime later in the month, and especially in early December. Also, some indications regarding higher pressures building into and near Greenland early to mid December. We all know the odds and the accuracy within the NAO domain, but well worth keeping tabs as we get closer to the holidays.

This is interesting, especially the what occurs after the first of the year, when the favored MJO phase(s) tends to change. This seems to be related to the Nina peaking in the OND period and then waning thereafter.

Expect the unexpected ..............

Let's re-visit this forecast in early December.

Not that it matters much, because the source region ( Canada ) is very warm at this time, but do you buy the + PNA look in early December? We are indeed getting unusual responses and progressions currently, as you mentioned. It will be fascinating to see what the pattern brings us in Jan and Feb where the majority of the seasonal consensus is little snow and much above normal temps. Hard to fight the warmer persistence whether from Nino or Nina like background states. But, I would still keep an eye open for the unusual outcome, in this new unusual climate recently.

Recalling last winter where robust West Coast ridging was forecasted a few times, only to breakdown or never develop, due to the compressed and rapid jet stream movement, culprits already discussed last year. But, if we can get a great Pac pattern in prime climo that lasts a week or more, maybe we can score. Watching the seasonal progression of shorter wave lenghts should be interesting as well later in December.

This does echo the thoughts of Isotherm's seasonal. We wait and watch. At the least the +PNA may help us from torching if indeed it develops.

@CAPE speculating that even if we get a +PNA what about the cold air source? If the EPS is correct Canada is very, very warm. Remarkable, and a sad situation for cold and snow lovers in the East. .