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Yep, active tracking continues, with two possible threats after Wednesday/Thursday event, with multiple shortwaves moving under the block. Been a very long time since we have tracked multiple threats in December. Stock up on coffee !

Wow ! Hello old friend I have missed you.

Also, a good sign for the rest of the winter. If the event happens, which is likely it appears, and is significant, it may portend the possibility of additional blocking episodes in January, February and March.

@CAPE in relation to the snow map above where are you ? In the the 3 inch color bar? I am straddling the 5 inch line, ( at the DC&D Canal ) which in the past at this range is a good signal for accumulating snow for my area. , Remember way back in 2003 I believe President Day 2 , I mixed, did you ? I am starting to get a bit excited, but knowing our area, tempering my enthusiasm. Looks like psu gets slammed.

GEFS and EPS worlds apart at this range. Have to see how long the block lingers.

Still learning and seeing how this cluster tool really performs. Also this post is more so geared across the pond. But looking at the forecast versus previous forecasts it appears the intense blocking forecasted near Greenland has shifted. I am interested in the EPS and GEFS runs this afternoon to see whether the always elusive Greenland blocking for fantasy land is starting to wash out and or shift more East.

@WxWatcher007 below normal air mass growing and on the advance in the latest 10 day mean.

Me too ! Anthony Masiello @antmasiello Looking forward to the 12/10 00z update. Poleward EP vectors! 10:34 PM · Dec 9, 2020

This look towards the end of December has changed for the better during the past 5 day period. Have not seen today's though.

@psuhoffman Liking the AAM tendencies and what they portend. I feel we can get a rather robust - NAO in the weeks ahead. Might coincide with an improving Pac and a growing cold air source to our NW.

Interesting to see how this evolves in the time period of interest near mid-month. Continued signs of HL blocking persist.

Finally seeing NW Canada turn below average temperature-wise. A good sign moving forward.

Potential in the NAO region and a negative NAM state will present opportunities certainly much better than last year at this time, we're heading in the opposite direction hopefully from where we were during the middle of December 2019.

Pretty sure last December 8 th this was going up, but I am old and can't totally recall.

Regarding the cryosphere, it is looking better with more NH snow cover, while Canada is getting colder. Hopefully, this has a role in January with direct cold air discharge when the pattern becomes more favorable .

Always an issue of timing as HM mentions, and yes coupling is indeed vital. One could speculate this year has a less hostile profile, possibly enabling an increased probability of coupling regarding the SSWE. Talk remains about the effect of last year's tropical fires upon the stratosphere. Seems the 15 th of this month, and the period just after, is key as to what may, or may not transpire.

There is hope. The look you posted puts pressure on the PV. May even improve the NAM state. And, we have all talked already about how the Atlantic may want to play this year in our favor, at least at times. There is growing evidence of a SSWE and even a possible reversal of zonal winds. Yes we want a weaker PV, not a beast, and yes we want HL blocking, but the eventual outcomes as it relates to our area, ( colder, snowier ) is really difficult to forecast. Do we experience a split, where does the PV re-locate to? We talked about this last year and the year before. Many times other areas of the NH benefit leaving us out of the severe cold and snowstorms. Granted, I will take my chances and see what develops in the weeks ahead.

The continuous, almost reliable knowledge, that high precip event are going to arrive shortly regardless of any five day period of dry weather has been going on for almost 24 months. You could make the case that in many of these high impact events, warmth was behind the reason why we achieved such a high precip in the first place. Active use to be a good indicator that eventually as we move deeper into winter the wet becomes white, but in this new base state this is yet another association that has lost value. That goes along with soil moisture as well . You can have a trough in the East and it can still rain in the heart of winter. Very frustrating too regarding recent storm tracks that favor areas North of us. I believe the SST pattern in the North Atlantic may have something to do with this.

As you know the Nina coupling is only getting stronger. Whether this lends further support to the weeklies is uncertain. I have read that the lag effect rules this possibility out. I respect what DT has stated, however, at least several mets and pros that I follow have stated by the time the Nina weakens and works it way into the atmospheric response we will be exiting our snow climo. I know you know all this, but I believe some have hopes set too high for a Nina year. But, looking at the weather acorss the country in 2020 with high precip events, extreme weather, etc. if there was every a winter to present a blizzard within this current base state, it is this winter.

Another positive we are seeing is AAM. As Matt noted below.

Wonder if Isotherm or Benchmark have data on the target locations of the PV in years where there was an actual SSWE in a moderate to strong Nina. Only issue or issues would be the value of the data in this present base state ( West Pac ), not to mention the very warm North Pac waters.

Doesn't that fit the seasonal modeling ? A progressively worse Pac. Shoulder months may still hold the best outcomes but I believe December is a so so month for us based on our location and climo. However in terms on the HL and the NAO domain there are some interesting tidbits. I would not hinge the hopes of winter on any SSWE. Just need to monitor and hope we get a two week period that delivers. It really is all we can hope for in this base state and Nina in general. And there really is something about a turn to warmer near the holidays, this will mark the 4 th year in a row most likely. Say what you want but it is uncanny.

I would love that!!!!! BRING IT !

Meanwhile we keep the PV in check throughout December, much better than last year. That raises the possibility of an improved NAM state in January, despite seasonal model calls. Maybe the appearence of the elusive - NAO as mentioned by others here as well. I like the recent trends of the AO . Also, few members of the 35 day GEFS family go Easterly, yes, not many, but more than a few days ago. All in all we stay in the game.

For late December, after the 20 th, looking likely we warm up, not surprisingly. Seems the models mostly correct warmer in this new multi-year base state. Euro doing poorly, similar to last year's forecast of a descending - EPO. What is even more so disturbing is the performance of the EPS and the forecast failure in this ensemble regarding the - EPO and now the complete change up. Once again modeling in this domain in general is not to be trusted. You can see below from Bamwx. The window near mid-month I think is trending more so to areas North of us. Nothing really inspiring any confidence we see any significant snow during the favored period, maybe snow showers, or a snow to rain scenario. However, you can never be certain this far out. Also, keep in mind the consistent theme of inland runner, coastal huggers and cutters. Ned to change that up to score anything meaningful manner in Jan or Feb. I am interested in the next + PNA period. Wondering though if once again our cold air source region will be a concern.Northwest Canada is finally getting a bit colder though.