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I feel this is great news. Regardless of the closet match, keep it going down. Hopefully this is another positive added to the mix for Jan through March. Some folks were concerned it might stall.

Reading from a met who stated some of those looks within a greater window of 30 days, not the date centered on 12/14 , so going towards and including 12/28 have produced some significant EC snow events, including significant over running snowfall producers going from the Tennessee Valley to the Northern Mid Atlantic. I am thinking he did a roll over from that CPC depiction, but not sure.

I will take an order of blizzard, a side of drifts and for dessert a gale or two.

Very true, he knows his stuff, but that does not give one the excuse to act like an ass to others . Being humble has advantages. Eating crow is on his menu today.

You know avoiding a massive and prolonged warm up in Canada, along with a loss of snow cover, similar to last December, in my opinion really ups the ante for severe arctic outbreaks here in our area. Snow cover to our North and Northwest is very impressive right now.

More on the possible NAO block from HM and his general thoughts about December. Great job so far Anthony ! Colder risks seem to be gaining traction lately.

Most excellent ! I totally agree, minute details in weather do matter, that is what makes this hobby so enjoyable. Next, I need snow, a lot of it please. I want to dust off the snowshoes.

Excellent animation by Hugo regarding the upcoming wave break in the North Atlantic. Gives more support to something near mid month. The evolution of any -NAO is still key to an any snow possibilities down our way. By this time we are deeper in December, will be interesting to see what transpires in the NAO domain the second and third weeks of December. Maybe the block times perfectly with some over-running moisture to our South, as signs are for an active STJ this month. Also, note the changes here beyond December 7 th : 00Z GEFS 1.0° 100 hPa 60°N tercile categories The tercile-category anomaly of the lower-stratospheric polar vortex, defined by the 100 hPa 60°N zonal-mean zonal wind, has been used as a diagnostic for the behaviour in the ‘coupling layer’ between the stratosphere and troposphere, i.e. the level in the stratosphere where circulation anomalies are important for influencing tropospheric weather regimes (e.g. Charlton-Perez et al. 2018, Lee et al. 2019). The chart below shows the percent of GEFS members in each tercile anomaly category, based on daily 1979-2018 ERA-5 climatology. Weak = lower tercile; neutral = middle tercile; strong = upper tercile.

A few interesting things to keep an eye on : The mid month period when there are signs of a drop in the AO along with a +PNA interval. Some favorable action too from the strat may work its way down to a degree. Meanwhile, interesting progressions with the warming as it transpires in terms of the Canadian vortex and trop / strat vortex over Siberia/Scandy , as mentioned by Hugo. Also, the elongation and the movement of the trop vortex has my interest as well, in a backdrop favorable to keep the vortex perturbed. Below are several relevant recent releases on the above.

Maybe we get lucky with some snow showers this week, but the way the current pattern looks, I think we need to wait a while. The various indices that are normally associated with accumulating snowfall in the Northern Mid-Atlantic our not in our favor moving forward. Yes, I know about scoring in flawed patterns, but with the time of the year, I have less confidence that happens this go around. The end of the month still seems to be uncertain, maybe we turn colder with opportunities later in the month.

I will gladly ride the BAMMWX train ......................where can I get my ticket ? By the way.....I still believe in snow and in holiday spirit. Hopefully, a nice time coming up for us soon for those who enjoy cold and winter scenes of snow covered fields and streets bounded with snow in a winter wonderland.

I admit there are some positives but as you know the GEFS is at times biased weak, at least so far this early season, while the EC has done better in strat verification forecasts. However, as you mention, we are talking under 7 days here with the GEFS, so that is a positive. Also, according to Simmon Lee the FV3 GFS has been doing better versus the GEFS. A quick note on the AO ensembles - seems the forecasted extreme positives, up to +5 or more, have been trimmed back down to about + 3, with several members taking the AO back negative shortly thereafter. As HM stated previously, the same processes causing the AO to rise will be responsible for the upcoming decline in the NAM state. Meanwhile, Matt is impressed by the potential down the road. We will also get an update soon regarding the QBO. There are some interesting evolution and progressions possible in mid- January if things work in our favor. This is of interest as well :

I understand your point.

Sorry, nothing is bogus here. Research is convincing that during this decade there has been impressive warming in the Indo-Pacific warm pool and changes in the behavior of the MJO. Since 2010 there has been a tendency for repetitive Fall patterns. If you don't agree with the data that is fine.

Do you follow Isotherm? I know he has spoken about the solar cycle and in various posts he has alluded to role the solar minimum has on potential impacts within the NAO domain. His seasonal prediction of the NAO has a very good record. I found some articles/research that seems to reveal a link between the years after the solar min, and the phase of the NAO. The interesting part is the lag effects. Seems it could take a year or two, maybe even longer for the impact to be reflected in the NAO domain. The link was SST based I believe.

I brought it up because it has been repeating lately in some form or fashion ( a 2010's weather theme, and you can read more about MJO study here ) https://www.nature.com/articles/s41586-019-1764-4 and this from @bluewave Yes, I just posted that in the climate change forum with all the charts included. The changes to the MJO have become a big part of our 2010’s weather patterns. It shows what we already figured out. The MJO has been spending more time in the Maritime Continent phases due to the rapid SST warming of the Indio-Pacific warm pool.

You believe we follow the same general progression this winter? I feel we will, but the colder risks will win out once past early Jan. Also, speculation on my part that we will deal with some significant phasing events and some very cold arctic intrusions. Simple guesswork reveals the best -EPO period/events in mid- Jan, and the best -NAO event in early to mid Feb and another opportunity in March. ( March to a degree dependent on the declining QBO and any SSW in late Jan. and early Feb) again just some thoughts there.

The much anticipated warm December is coming. Simply can not fight the deep tropics. The same concerns last year regarding the MJO that lasted in the warm phases for weeks on end may repeat again this December. The latest AO forecast do not look as good today, the NAO going up. Source regions are warming. The camp that predicted an overall warm December is a step closer to possibly being correct. Early December this year similar to last year, and then we warm. Whether it lasts two weeks or longer is still hard to pin down. The consistency of the last few years of the pronounced warm up post 12/20 is an increasing risk again this December. There is a repeating pattern of late.... warm Octobers , cold Novembers, Decembers turning warmer after the first week. There could be a delay this December with the cold winning out until the 10th, but still looking like we warm once past the 10th. I will also mention new research reinforces that the idea in which the MJO is spending more time in the warmer phases while racing through the cold phases. This is pronounced in the time period from 2010 forward.

There does seem to be some differences to last year at time, with possibly a bit less amplitude. Last year was agony though, with the slow progression through the warm phases, and that lasted well into Jan. if I recall correctly.

Do you think we ever see this trend reverse ? And, would you speculate that it can potentially reduce the chances of an extended period of severe and durable cold weather locking in here in the East , of the magnitude we saw at times in the late 1970's ?

Wondering whether this new research has a link to warmer temps via the MJO phase progression, and the shortened period of cold, regardless of time of year, due to the fact the MJO is spending more time in the warmer phases, as the Indo-Pacific warm pool is effecting the MJO via progression and life cycle. research link https://www.nature.com/articles/s41586-019-1764-4

Interesting post by Isotherm from 33. Posted 1 hour ago Other proxies of northern hemispheric, vortex status indicate the predilection for lower-geopotential heights in the Arctic domain, but particularly the NAO domain in the means, as delineated in my outlook. November 2019 ozone data evinces generally lower concentrations near/over Greenland to the north of Europe. When juxtaposed with the mean November climatological ozone, it has generally been less extensive in those domains. Moreover, the polar vortex area is now running well above normal, circa 30 million km^2. Expansion in vortex area is generally a precursor / presages tropospheric NAM significant incline. Again, as Don alluded to above, while aesthetically pleasing stratospheric maps continue to be circulated, it's integral to examine exactly what is transpiring in the troposphere as far as the veridical data. SPV intensity diminution doesn't always correlate directly to tropospheric vortex status.

I am looking at zonal winds at 10 mb. But, as you mentioned , and also brought up by HM indirectly, is this set-up forecasted by both the Euro and the GFS. On a side note, I have not looked today, but hearing the wave 2 follow-up may not be as significant then first thought for early to mid- December. A lot will change moving forward, no worries there yet.

And yeah, steady as she goes .....

The way things are going right now with the vortex is probably the best outcome, more or less. Speculating that we don't have a major SSW in December, ( at least that is what the current modeling shows and echoed by some strat experts ) Sometimes the rare very early season SSW can interfere with things and many times the vortex recovers. Having any type of major SWWE later versus early can possibly extend our winter weather potential. Of course, we would have to be lucky in that respect and be the area of focus. And, I know you know this poolz1 , but we have already experienced a minor warming and it appears yet another minor warming is anticipated in the first half of December. So things are looking good a bit down the line. Oh, and for the record, I feel robust blocking returns and coincides with a split flow pattern, leading to a memorable period of winter storms in January and beyond.