You notice warm anomalies in the east while the west stays cool. This would not be the winter that we are looking for in terms of cold and snow.
My second analog set would be el nino years following a double or triple la nina, with a positive PDO in the winter months although still negative in a decadal sense. Every year except for 2002-03 is in a cold PDO phase overall but the coming El Nino causes the PDO to flip to positive for the winter and spring months. I also chose years with a warm AMO, expect for 1976-77. My years are 1957-58, 1976-77, 2009-10 and 2002-03. Now I know that some people do not want to include years following a triple nina but I believe that those years should be included in the analog set and share many similarities to double nina's anyways. Here is what these years looked like.
So in order to produce an analog set you want to include all the possible variables, so it is important as I had shown before with my MEI analogs that all the players are on the table here. As we can see most of the time when the AMO is positive, and an el nino is coming off a la nina or two la nines/ three la nines you get a positive PDO as well even though its overall negative. For example 57-58, 09-10, 76-77. 51-52 went the other way with the same positive AMO, cold PDO overall and nino off of la nina. Notice 1951-52 is the only year that is following just a single la nina. This is good news for us because this may be showing that if you are coming off of a multiple nina in a warm AMO your chances of a warm PDO spike is better.
Now what if the AMO stays colder then what will happen. There is a cold signal here as well with three years that I found were 1965-66, 1976-77 and 1972-73. This scenario probably would be cold as well. 72-73 ended up with a cold PDO winter and a warm winter overall and 1965-66 and 1976-77 had cold winters across the east. This cold AMO scenario seems unfavourable at the moment so until we see signs this may occur it probably won't and all modelling I've seen is hinting the other way.
NAO values for dec-feb:
1951 12 1.13 1952 1 0.57 1952 2 -1.38
You could argue the warm water detached from the south american coast is the driver but all these years have this and we still see the differences in blocking and cold.1957 12 0.021958 1 -1.141958 2 -1.642009 12 -1.882010 1 -1.802010 2 -2.69Cold AMO years:1972 12 0.09 1973 1 -0.46 1973 2 0.52Compared Too:1976 12 -1.571977 1 -1.721977 2 -1.00Somebody could argue that the QBO would be the cause of blocking or no blocking in these winters (similar to the upcoming one). The winter of 1972-73 had a negative QBO but could still not develop a block due to the PDO which remained negative. QBO values from dec-feb 1972-73.-16.78 -4.40 0.08Same case in 1951-52:-3.98 -6.80 -7.71
Now the only difference between these years is the PDO which spiked in all the years except for 1951-52 and 1972-73. I think we are seeing a strong correlation between the NAO going negative and the PDO flipping to warm giving just another reason why the flip of the PDO is the most important driver with regards to next winter. This will occur by the warmth shifting into nino 3.4 which its forecasted to do.
Taking a look at the current AAO which is already strongly negative and is forecast to dip below -3. A negative AAO in the summer is usually an indication that we will see blocking during our winter. We are already seeing a pattern that is capable of producing strong blocking(shown this week) and we are seeing a much different pattern then last winter where no blocking was found.
I hope you appreciate the important links I showed you and the work it took to dig this up. I am trying to show you why the NAO was so negative in these years and how they match up to our current pattern. I'm not just saying 1951-52 and 1972-73 were warm winters because the NAO was positive, it is why the NAO was positive which controlled the pattern in these winters. Please feel free to leave comments!