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Only this year, and in this new warmer background state, does a deep - AO and -NAO produce no significant snowfall for us. Source region concerns continue, and even though the +EAMT events are helping with the -NAO they are also bringing in copious warmth to Alaska . At our latitude we need perfection and it is just not there. The fast flow and uncooperative Pac is over-powering the - AO and -NAO. How long this lasts is still uncertain , but hopefully by mid month the Pac changes up a bit. At the moment the really cold air is in Asia, as you have read about the very strong high pressure areas there.

We need at @Isotherm to come in here and do a little updating. I believe according to his seasonal forecast , January held the highest probabilities of colder with normal to above normal snowfall for our area.

Goes to show, both humans and models still possess debatable value beyond a certain point.

Ark like rains here , warnings flying across the radios and TVs, Rudolph is wearing scuba gear.

Hard to be a believer after a run like that.

EPS at 360 hours has an awesome Greenland block in the Davis Straights with another incoming +EAMT event. Maybe spur a +PNA . Mid to late Jan. could rock.

Donald Sutherland did some posting about the CFS last winter, and its accuracy for the month ahead. What he found was it really gets into its wheelhouse of accuracy around this time of the month for the month ahead. So, it would appear you can place a little more faith on the CFS at this time.

Hearing about concerns related to source regions from several mets. This went in the wrong direction, hopefully by mid Jan this looks much different. CFS progression makes sense, so it is not out there alone with bringing improvements in the EPO region.

This is a long range thread ? Gathering unique, useful data and weighing it for long range outcomes is the fun part of long range forecasting.

7 x more likely. Good odds. @SimonLeeWx Replying to @SimonLeeWx The Arctic High regime is ~7x more likely to occur if the lower-strat vortex is weak than strong (https://doi.org/10.1029/2019GL085592…) - and that's certainly consistent with this forecast. Suggests that the accuracy of the stratospheric forecast may be important here for the regime forecast. Wintertime North American Weather Regimes and the Arctic Stratospheric Polar Vortex agupubs.onlinelibrary.wiley.com

Overall probability is reassuring that the Greenland blocking regime is indeed real. @SimonLeeWx Tropospheric-led but then subsequently likely reinforced by the weakened stratospheric vortex, the GEFS 35-day shows an unusually strong signal for the Arctic High regime (Greenland blocking) to dominate the North American regime space over the coming few weeks. 11:12 AM · Dec 23, 2020·Twitter

Progression could be cuter, cuter. Mid Atlantic snowstorm then clipper, then classic Miller A third week of Jan. It fits evolution of NAO block retro and then Pac improvement based on forcing moving into more favorable area / +EAMT events and then a rise off of a deep -NAO sort of similar to a HA event.

Damn !!!! I like!!! Eric Webb @webberweather This is the composite of Jan-Febs that had late Dec-Jan SSWEs & whose tropospheric pattern in the 3 weeks leading up to the SSWE bears some semblance to this yr (+WPO/+EPO/-NAO/-AO/+SCAND). Very NINO heavy composite as you'd probably expect given the deep, precursor Aleutian Low 11:42 AM · Dec 23, 2020

Hasn't the GEFS out-schooled the EPS, or is it my imagination? Thought a couple mets commented on that last week.

He probably did jump the gun, but the pattern that he spoke about may very well develop in time. The Nao and the Arctic oscillation point to the possibility of winter storm threats in the East at some point in January.

There has been a tendency for Inland Runners and Coastal huggers but the Dynamics of the block have to fully mature, the best chances most likely after the 7th of January.

Looking forward to the next update, but this is rather impressive and starts in only a few days,

Member count continues to increase.

Seems as though there will be multiple +EAMT events upcoming. Hopefully, this provides a few +PNA intervals, coinciding with a storm threat for us in January.

OMG, spit my sugar smacks out. At least your odds are 10 % , I am at zero.

The long range GFS matches the new CFS for Jan. 2021 , which according to the date today of the 22 nd should be entering its period of higher verification for the next 30 day period. I like ! We track ! @psuhoffman you think ridge bridge way out there possible.

Hopefully, I get a new coffee maker for Christmas along with an extensive variety of coffees to fuel the late nights of tracking in Jan.

Onto a new CAPE era, bring us luck please

I am with you regarding your thoughts and progressions. Seems colder air gets involved later, but we could score with typical cold as we near better climo. Strat is preconditioned and the trop is receptive to the incoming and ongoing SSWE. Also, as HM alluded to, the timing of this event is very good, nothing really on the table to interfere. In the past the high amp MJO and Pac features made the SSWE useless and entered chaos into seasonal forecasts. This time the brunt of the hoped for benefits seems to NA and the Eastern US in time. As several strat experts have mentioned nothing is a slam dunk in long range forecasting, but so far it looks good and the event is becoming more likely as well. The expansive event getting underway in Siberia will hopefully lead us to a more conducive period of +PNA. Meanwhile very cold air should begin to pool and grow in coverage in Central Canada. Get that Greenland blovk to retro as well and the bar is raised. Looking at the lastest GFS NH polar vortex ellipse time lapse forecast, it seems to place us in a interesting location as the SSWE progresses. Also of interest, is Anthony's post yesterday regarding the pv, strat, and the warming, etc. He mentioned the event itself may, depending how it evolves, could create it's own regime. I thought that was a very interesting comment.