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JMA weeklies..... Yikes ! FYI.... I rotated the image aleady.

Wow, have not seen a AO forecast like this in December for many a year. Usually it is going towards + 4. Bring on winter !

Did you happen to check out the extended, GFS? It shows a continuation of blocking. According to HM the mechanisms to support the North Atlantic blocking are supposed to cycle and repeat. You also have to wonder if what occurred in the southern hemisphere during winter is going to occur in the northern hemisphere during our winter.

Data and image Coutesy of Don Sutherland @donsutherland1 Neutral to + PNA certainly raises the odds of snowfall for many locatioins in this image.

As Anthony had mentioned previously, this - NAO regime is not the only one for this winter season. .

Wow, that Greenland block is changing the entire waveguide up North. Incredible ! According to @burgwx the delayed effect of the block puts the highest risk for a major snowstorm between the 15 th and the 20 th. I would like an appetizer and then the Big dog . Woof !!!

When Allan gets excited I know its the real deal.

Just more data on how significant this upcoming Greenland blocking event is going to be.

Yes, signs point to a significant - EPO reload. Of note as well, are signs of a warming event near the pole. The pattern is locked and loaded it would appear. Should the pattern evolve as modeled significant snow cover will be located to our North and West and maybe over our region as well. Appears that the cryosphere will be healthy to deliver the possibility of intense cold originating in NW Canada then moving SE over snow covered grounds with little moderation at a time of very low sun angle and solar output. Something not seen in a very, very long time. A 1960s analog type deal. Also, this is the last day of the month so I give the CFS a decent chance of verifying for December. It should be in its wheelhouse of best skill for the next month.

@CAPE big storm potential leading up to Christmas.

This look appears as one of the more colder and aggressive clusters from @burgwx that he posted yesterday.

There certainly is a connection, just need to find the research. I have read that a - 3 AO in December, or possibly earlier, tend to get repeated during the winter. If a - NAO episode is involved as well it raises the bar for our area and the low lands.

Wow that was awesome ! I know he is a master of using ensemble clustering. He has tons of data where he can compare current modeling to past ensemble clusters.

Well, the cold and storm trifecta you refer to there is actually a possibility based on the evolution of the modeling, but it is only modeling, so...... The - EPO regime should return, the AO is forecast to stay mostly negative, the - NAO may be reinfoirced with wave breaking, the zonal winds are forecast to remain weak or go weaker, the PV is disturbed , and I believe you need low zonal winds to foster a prolonged - NAO period. That is one crazy look.

Well, the I believe the JI emotioanl equation is ( negative Ji ) + ( JI loves snow ) + ( - AO ) + ( - NAO ) + ( - EPO ) = Happy JI

If the AO can achieve - 3 during this coming December it would really mean a lot towards a favorable winter pattern with increased odds of snowfall and cold in the East. The last four days the trends have been increasingly negative.

Christmas snow has real potential this year, and even beyond as a -EPO regime likely begins later in December. Could be a very interesting period prior to Christmas and leading into the New Year. As Eric mentions, this was Anthony's call from mid November. There is also significant clustering from the EPS ( from BAMWX ) today that shows the potential for a very cold and active weather pattern in the East beyond the middle of December.

Ha ha , wonder is Simon calls his wife hey, phwoar... I had to Google it too !

Even though he is off by 1 for the record, it is still pretty remarkable and the GEFS is near 1060 mb. Wow ! Here is the JMA at 1065

Several interesting developments to keep track of moving forward: The rapid snow cover extent in the NH, and thoughts about the Hunga-Tonga Volcano erruption in Dec. 2021 and effects on the PV. ...

As many here already know, the skill of the CFS model for the next month is highest after the 27 th day of the month prior to the forecast given. Therefore, the current modeling by the CFS for this coming December may not be very far-fetched. Of note, there is a signal here later in December for increased moisture potential in the East. Might be from a Miller A or Miller B, hard to tell, but the signal is there.

Morning view from the GEFS I believe this is near @CAPE 's favored window for snowfall.

As @Bob Chill mentioned there is a relationship between December strong - NAO ( - 1.2 or less ) and the following months of January and February. Data from Allan Huffman

Agreed. I don't want to set expectations too high. Happy to track the evolution of the cold and maybe we avoid the recent string of warm days after the 20th of December in recent years.

Regarding the block.