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Wintry Winter 25-26 Winter Battle Zone

I don't want to see the pna too positive or see it too negative. That's why it's very difficult to get winter weather in the south
We tend to score at the end of +PNA patterns. A spiked +PNA really helps if we get energy diving out of Canada or the PNW, but generally we tend to score after a period of +PNA and as we are trending to a neutral. Too much west coast ridging, especially coupled with a -NAO and we just send the freezer down here and end up with sunny and 25 degree days. Very very fine line
 
We tend to score at the end of +PNA patterns. A spiked +PNA really helps if we get energy diving out of Canada or the PNW, but generally we tend to score after a period of +PNA and as we are trending to a neutral. Too much west coast ridging, especially coupled with a -NAO and we just send the freezer down here and end up with sunny and 25 degree days. Very very fine line
Always very difficult here. Get cold established and take our chances from there
 
Guys a spiked PNA is always is a good thing. Let me pick only one TC and a posotive PNA is always numero uno! #2 is atlantic blocking, -nao's an 50/50 lows etc, to slow flow and lock the cold air coming down out of canada in. We will get the ns energy this winter with a + pna , no problem. Problem will be hunting some ss energy to generate a phaser or two. Expect a lot of upslope snows this year, esp first 2/3 rds of winter . Aka, have the Jimmy roadtrip plan developed on standby. After about 4 or 5 downslope screw jobs, just take a 90 min trip up top.
 
We tend to score at the end of +PNA patterns. A spiked +PNA really helps if we get energy diving out of Canada or the PNW, but generally we tend to score after a period of +PNA and as we are trending to a neutral. Too much west coast ridging, especially coupled with a -NAO and we just send the freezer down here and end up with sunny and 25 degree days. Very very fine line
IDK. I guess my biggest thing with the PNA is just don’t let it be strongly negative and I’ll take my chances with cold close by and strong blocking up north. Some of the best storms I’ve gotten to experience, including February 2004, and the 2010 Christmas storm, took place with a -PNA. While I’ve seen so many times a strongly + PNA suppress everything way south and we end up cold and dry.
 
Guys a spiked PNA is always is a good thing. Let me pick only one TC and a posotive PNA is always numero uno! #2 is atlantic blocking, -nao's an 50/50 lows etc, to slow flow and lock the cold air coming down out of canada in. We will get the ns energy this winter with a + pna , no problem. Problem will be hunting some ss energy to generate a phaser or two. Expect a lot of upslope snows this year, esp first 2/3 rds of winter . Aka, have the Jimmy roadtrip plan developed on standby. After about 4 or 5 downslope screw jobs, just take a 90 min trip up top.
According to multiple studies of NC winter storms, of all the indicies, a -NAO is the most common thing in place. I’m not saying a +PNA is bad, I’m just pointing out that there have been a number of great storms that saw a neutral or slightly -PNA
 
According to multiple studies of NC winter storms, of all the indicies, a -NAO is the most common thing in place. I’m not saying a +PNA is bad, I’m just pointing out that there have been a number of great storms that saw a neutral or slightly -PNA

Interestingly, my own analysis first done several years ago and posted here actually did find a +PNA more common than a -NAO for 6”+ RDU winter storms:


21 RDU 6”+ snowstorms since 1950

1/19/1955 Niña neut PNA, neut AO, moderate -NAO

12/11/1958 mod +PNA, neut AO and NAO

3/2-3/1960 mod -PNA, neut AO and NAO

3/9/1960 weak -PNA, strong -AO, neutral NAO

2/26/1963 -neutral strong +PNA, mod +AO, neutral NAO

1/26/1966 neut PNA, strong -AO and -NAO

2/9/1967 -neutral mod +PNA, weak +AO, moderate +NAO

3/1/1969 strong +PNA/-AO, moderate -NAO

1/7-8/1973 weak +PNA, neut AO, strong -NAO

2/18-9/1979 neut PNA/AO/NAO

3/1-2/1980 neut PNA/AO, moderate +NAO

3/24/1983 mod +PNA/-AO, neutral NAO

2/6/1984 -neutral mod +PNA/+AO, strong +NAO

1/7/1988 mod +PNA, neut AO, weak +NAO

2/17-8/1989 Niña neut PNA, strong +AO/+NAO

1/24-5/2000 Niña mod +PNA, neut AO, moderate -NAO

1/2-3/2002 -neutral strong +PNA, neut AO, moderate -NAO

2/26-7/2004 neut PNA, strong -AO, weak -NAO

12/26/2010 Niña weak -PNA, strong -AO, moderate -NAO

1/17/2018 Niña neut PNA, weak +AO, strong +NAO

12/9-10/2018 mod +PNA, neut AO, moderate +NAO
—————————

For the 21 storms

-11 (52%) +PNA, 7 (33%) neutral PNA, 3 (14%) -PNA

-7 (33%) +NAO, 6 (29%) neutral NAO, 8 (38%) -NAO

So, whereas 52% had a +PNA vs only 14% with a -PNA, 38% had a -NAO vs 33% with a +NAO

So, whereas there were almost 4 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been much more balanced.
————

The above is for all ENSO.
What about for just -ENSO?

-5 (56%) +PNA, 3 (33%) neutral PNA, 1 (5%) -PNA

-4 (44%) +NAO, 1 (11%) neutral NAO, 4 (44%) -NAO

So, whereas 56% had a +PNA vs only 5% with a -PNA, 44% had a -NAO vs 44% with a +NAO

So, whereas there were 5 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been totally balanced.


Daily PNA link:


Daily NAO link:
[/b][/b]
 
Interestingly, my own analysis first done several years ago and posted here actually did find a +PNA more common than a -NAO for 6”+ RDU winter storms:


21 RDU 6”+ snowstorms since 1950

1/19/1955 Niña neut PNA, neut AO, moderate -NAO

12/11/1958 mod +PNA, neut AO and NAO

3/2-3/1960 mod -PNA, neut AO and NAO

3/9/1960 weak -PNA, strong -AO, neutral NAO

2/26/1963 -neutral strong +PNA, mod +AO, neutral NAO

1/26/1966 neut PNA, strong -AO and -NAO

2/9/1967 -neutral mod +PNA, weak +AO, moderate +NAO

3/1/1969 strong +PNA/-AO, moderate -NAO

1/7-8/1973 weak +PNA, neut AO, strong -NAO

2/18-9/1979 neut PNA/AO/NAO

3/1-2/1980 neut PNA/AO, moderate +NAO

3/24/1983 mod +PNA/-AO, neutral NAO

2/6/1984 -neutral mod +PNA/+AO, strong +NAO

1/7/1988 mod +PNA, neut AO, weak +NAO

2/17-8/1989 Niña neut PNA, strong +AO/+NAO

1/24-5/2000 Niña mod +PNA, neut AO, moderate -NAO

1/2-3/2002 -neutral strong +PNA, neut AO, moderate -NAO

2/26-7/2004 neut PNA, strong -AO, weak -NAO

12/26/2010 Niña weak -PNA, strong -AO, moderate -NAO

1/17/2018 Niña neut PNA, weak +AO, strong +NAO

12/9-10/2018 mod +PNA, neut AO, moderate +NAO
—————————

For the 21 storms

-11 (52%) +PNA, 7 (33%) neutral PNA, 3 (14%) -PNA

-7 (33%) +NAO, 6 (29%) neutral NAO, 8 (38%) -NAO

So, whereas 52% had a +PNA vs only 14% with a -PNA, 38% had a -NAO vs 33% with a +NAO

So, whereas there were almost 4 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been much more balanced.
————

The above is for all ENSO.
What about for just -ENSO?

-5 (56%) +PNA, 3 (33%) neutral PNA, 1 (5%) -PNA

-4 (44%) +NAO, 1 (11%) neutral NAO, 4 (44%) -NAO

So, whereas 56% had a +PNA vs only 5% with a -PNA, 44% had a -NAO vs 44% with a +NAO

So, whereas there were 5 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been totally balanced.


Daily PNA link:


Daily NAO link:
[/b][/b]
I'd bet the correlation between winter storms and a positive PNA is even stronger for those of us further south.
 
Interestingly, my own analysis first done several years ago and posted here actually did find a +PNA more common than a -NAO for 6”+ RDU winter storms:


21 RDU 6”+ snowstorms since 1950

1/19/1955 Niña neut PNA, neut AO, moderate -NAO

12/11/1958 mod +PNA, neut AO and NAO

3/2-3/1960 mod -PNA, neut AO and NAO

3/9/1960 weak -PNA, strong -AO, neutral NAO

2/26/1963 -neutral strong +PNA, mod +AO, neutral NAO

1/26/1966 neut PNA, strong -AO and -NAO

2/9/1967 -neutral mod +PNA, weak +AO, moderate +NAO

3/1/1969 strong +PNA/-AO, moderate -NAO

1/7-8/1973 weak +PNA, neut AO, strong -NAO

2/18-9/1979 neut PNA/AO/NAO

3/1-2/1980 neut PNA/AO, moderate +NAO

3/24/1983 mod +PNA/-AO, neutral NAO

2/6/1984 -neutral mod +PNA/+AO, strong +NAO

1/7/1988 mod +PNA, neut AO, weak +NAO

2/17-8/1989 Niña neut PNA, strong +AO/+NAO

1/24-5/2000 Niña mod +PNA, neut AO, moderate -NAO

1/2-3/2002 -neutral strong +PNA, neut AO, moderate -NAO

2/26-7/2004 neut PNA, strong -AO, weak -NAO

12/26/2010 Niña weak -PNA, strong -AO, moderate -NAO

1/17/2018 Niña neut PNA, weak +AO, strong +NAO

12/9-10/2018 mod +PNA, neut AO, moderate +NAO
—————————

For the 21 storms

-11 (52%) +PNA, 7 (33%) neutral PNA, 3 (14%) -PNA

-7 (33%) +NAO, 6 (29%) neutral NAO, 8 (38%) -NAO

So, whereas 52% had a +PNA vs only 14% with a -PNA, 38% had a -NAO vs 33% with a +NAO

So, whereas there were almost 4 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been much more balanced.
————

The above is for all ENSO.
What about for just -ENSO?

-5 (56%) +PNA, 3 (33%) neutral PNA, 1 (5%) -PNA

-4 (44%) +NAO, 1 (11%) neutral NAO, 4 (44%) -NAO

So, whereas 56% had a +PNA vs only 5% with a -PNA, 44% had a -NAO vs 44% with a +NAO

So, whereas there were 5 times as many with a +PNA vs a -PNA, -NAO vs +NAO has been totally balanced.


Daily PNA link:


Daily NAO link:
[/b][/b]
I wonder what it like for GSO and CLT. I bring that up because I know that the studies done by the NC State Climate office, one or which I believe Webb did if I’m not mistaken, showed that the most common of the indicies to prevalent for NC winter storms outside the mountains is the -NAO
 
We got flurries on November 10th. That was it. Everything else is fantasy and will be pushed back with every model run.
Don't mind a little push back/delay actually. Prefer to hit climo in mby. Very late December and first 2/3rds of January. Of course a Christmas storm is always nice for anyone
 
I always get nervous in nina years. The payouts can be amazing but we can always get years like 01-02 and 05-06 where we go hard for a while early then it's just dead. That said I think we can milk this one until at least mid Jan before oof, womp, 3 iron.

And as for December, it looks fine. Timing is a big different than the last few nina winters with the torch before and into Thanksgiving then cold in early December. I wouldn't be shocked though to see a cold start, relaxation in mid December, then renewed cold around Christmas into the new year
 
I wonder what it like for GSO and CLT. I bring that up because I know that the studies done by the NC State Climate office, one or which I believe Webb did if I’m not mistaken, showed that the most common of the indicies to prevalent for NC winter storms outside the mountains is the -NAO

I hadn’t done a compilation for those 2 cities. But I just took a look at the NAO and PNA for the 16 6”+ GSO storms that weren’t also 6”+ at RDU out of curiosity:

2/26/1952: neutral NAO, strong +PNA

1/22-24/1954: moderate +NAO, moderate -PNA

2/15/1958: neutral NAO, strong +PNA

2/13/1960: strong -NAO, neutral PNA

1/1/1962: moderate -NAO, moderate +PNA

1/29-30/1966: strong -NAO, weak +PNA

12/16-17/1973: weak +NAO, weak +PNA

3/22-23/1981: neutral NAO, moderate +PNA

1/12-14/1982: neutral NAO, neutral PNA

1/22/1987: moderate -NAO, moderate +PNA

2/27/1987: weak -NAO, neutral PNA

1/6-7/1996: moderate -NAO, weak +PNA

1/29-30/2010: weak -NAO, weak +PNA

2/12-13/2014: moderate +NAO, strong -PNA

2/24-26/2015: strong +NAO, weak -PNA

1/6-7/2017: moderate +NAO, moderate -PNA
—————

So, for the 16 GSO 6”+ storms not also at RDU:
- 5 (31%) +NAO, 4 (25%) neutral NAO, 7 (44%) -NAO

- 9 (56%) +PNA, 3 (19%) neutral PNA, 4 (25%) -PNA

-So, for the 16 6”+ storms at GSO that weren’t also at RDU, the stats show 56% +PNA vs 44% -NAO.

-This compares similarly to the 52% PNA to 38% -NAO for the other 21 6”+ storms.

-So, GSO is similar to RDU in showing a +PNA to be more prevalent than a -NAO for 6”+ storms.

——————
Charlotte and Atlanta won’t be much different. I already checked Atlanta years ago and found similar results favoring +PNA over -NAO.

My definition of neutral is -0.25 to +0.25

@NCSNOW

*Edited for correction
 
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I hadn’t done a compilation for those 2 cities. But I just took a look at the NAO and PNA for the 17 6”+ GSO storms that weren’t also 6”+ at RDU out of curiosity:

2/26/1952: neutral NAO, strong +PNA

1/22-24/1954: moderate +NAO, moderate -PNA

2/15/1958: neutral NAO, strong +PNA

2/13/1960: strong -NAO, neutral PNA

1/1/1962: moderate -NAO, moderate +PNA

1/29-30/1966: strong -NAO, weak +PNA

12/16-17/1973: weak +NAO, weak +PNA

3/22-23/1981: neutral NAO, moderate +PNA

1/12-14/1982: neutral NAO, neutral PNA

1/22/1987: moderate -NAO, moderate +PNA

2/27/1987: weak -NAO, neutral PNA

1/6-7/1996: moderate -NAO, weak +PNA

1/29-30/2010: weak -NAO, weak +PNA

2/12-13/2014: moderate +NAO, strong -PNA

2/24-26/2015: strong +NAO, weak -PNA

1/6-7/2017: moderate +NAO, moderate -PNA

12/9/2018: strong +NAO, moderate +PNA
—————

So, for the 17 GSO 6”+ storms not also at RDU:
- 6 (35%) +NAO, 4 (24%) neutral NAO, 7 (41%) -NAO

- 10 (59%) +PNA, 3 (18%) neutral PNA, 4 (24%) -PNA

-So, for the 17 6”+ storms at GSO that weren’t also at RDU, the stats show 59% +PNA vs 41% -NAO.

-This compares similarly to the 52% PNA to 38% -NAO for the other 21 6”+ storms.

-So, GSO is similar to RDU in showing a +PNA to be more prevalent than a -NAO for 6”+ storms.

——————
Charlotte and Atlanta won’t be much different. I already checked Atlanta years ago and found similar results favoring +PNA over -NAO.

My definition of neutral is -0.25 to +0.25

@NCSNOW

Variables and details always matter in this discussion IMO. -NAO with a trough off of greenland and ridging in greenland proper is one thing that will likely not do us much good without a proper pacific +PNA/-EPO mix. However if a lobe of the trop PV is trapped north of Maine under a beauty of a block then that can do the trick without a favorable pacific....if there's cold air to wedge down on us from the north.

Absent of a real PV trap though, I'd agree pacific rules the SE roost. If the jet doesn't allow cold to enter the conus, it won't matter what a minor -NAO will do with the storm track if the conus is warm. To me we're always in the game with cold nearby and the pacific brings the cold.

Maybe we get both in December and remove all doubt, lol.
 
Variables and details always matter in this discussion IMO. -NAO with a trough off of greenland and ridging in greenland proper is one thing that will likely not do us much good without a proper pacific +PNA/-EPO mix. However if a lobe of the trop PV is trapped north of Maine under a beauty of a block then that can do the trick without a favorable pacific....if there's cold air to wedge down on us from the north.

Absent of a real PV trap though, I'd agree pacific rules the SE roost. If the jet doesn't allow cold to enter the conus, it won't matter what a minor -NAO will do with the storm track if the conus is warm. To me we're always in the game with cold nearby and the pacific brings the cold.

Maybe we get both in December and remove all doubt, lol.

Interestingly, looking back at my two tables of big storms, the last 5 (2014-18) were all with a moderate to strong +NAO!! So, there hasn’t been even one 6”+ snow at either RDU or GSO with a -NAO (even a weak one) since way back on 12/26/2010!!

*Edited for correction
 
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I just noticed this for the 21 RDU big snowstorms for the AO:

5 +AO, 10 neutral AO, 6 -AO

So, neutral has been favored.
 
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I hadn’t done a compilation for those 2 cities. But I just took a look at the NAO and PNA for the 17 6”+ GSO storms that weren’t also 6”+ at RDU out of curiosity:

2/26/1952: neutral NAO, strong +PNA

1/22-24/1954: moderate +NAO, moderate -PNA

2/15/1958: neutral NAO, strong +PNA

2/13/1960: strong -NAO, neutral PNA

1/1/1962: moderate -NAO, moderate +PNA

1/29-30/1966: strong -NAO, weak +PNA

12/16-17/1973: weak +NAO, weak +PNA

3/22-23/1981: neutral NAO, moderate +PNA

1/12-14/1982: neutral NAO, neutral PNA

1/22/1987: moderate -NAO, moderate +PNA

2/27/1987: weak -NAO, neutral PNA

1/6-7/1996: moderate -NAO, weak +PNA

1/29-30/2010: weak -NAO, weak +PNA

2/12-13/2014: moderate +NAO, strong -PNA

2/24-26/2015: strong +NAO, weak -PNA

1/6-7/2017: moderate +NAO, moderate -PNA

12/9/2018: strong +NAO, moderate +PNA
—————

So, for the 17 GSO 6”+ storms not also at RDU:
- 6 (35%) +NAO, 4 (24%) neutral NAO, 7 (41%) -NAO

- 10 (59%) +PNA, 3 (18%) neutral PNA, 4 (24%) -PNA

-So, for the 17 6”+ storms at GSO that weren’t also at RDU, the stats show 59% +PNA vs 41% -NAO.

-This compares similarly to the 52% PNA to 38% -NAO for the other 21 6”+ storms.

-So, GSO is similar to RDU in showing a +PNA to be more prevalent than a -NAO for 6”+ storms.

——————
Charlotte and Atlanta won’t be much different. I already checked Atlanta years ago and found similar results favoring +PNA over -NAO.

My definition of neutral is -0.25 to +0.25

@NCSNOW
Very cool to look through this!

I guess the other question is what percentage of +PNA -AO -NAO conditions have yielded 6+ inches of snow. Granted, that may be a little harder to figure out.
 
I hadn’t done a compilation for those 2 cities. But I just took a look at the NAO and PNA for the 17 6”+ GSO storms that weren’t also 6”+ at RDU out of curiosity:

2/26/1952: neutral NAO, strong +PNA

1/22-24/1954: moderate +NAO, moderate -PNA

2/15/1958: neutral NAO, strong +PNA

2/13/1960: strong -NAO, neutral PNA

1/1/1962: moderate -NAO, moderate +PNA

1/29-30/1966: strong -NAO, weak +PNA

12/16-17/1973: weak +NAO, weak +PNA

3/22-23/1981: neutral NAO, moderate +PNA

1/12-14/1982: neutral NAO, neutral PNA

1/22/1987: moderate -NAO, moderate +PNA

2/27/1987: weak -NAO, neutral PNA

1/6-7/1996: moderate -NAO, weak +PNA

1/29-30/2010: weak -NAO, weak +PNA

2/12-13/2014: moderate +NAO, strong -PNA

2/24-26/2015: strong +NAO, weak -PNA

1/6-7/2017: moderate +NAO, moderate -PNA

12/9/2018: strong +NAO, moderate +PNA
—————

So, for the 17 GSO 6”+ storms not also at RDU:
- 6 (35%) +NAO, 4 (24%) neutral NAO, 7 (41%) -NAO

- 10 (59%) +PNA, 3 (18%) neutral PNA, 4 (24%) -PNA

-So, for the 17 6”+ storms at GSO that weren’t also at RDU, the stats show 59% +PNA vs 41% -NAO.

-This compares similarly to the 52% PNA to 38% -NAO for the other 21 6”+ storms.

-So, GSO is similar to RDU in showing a +PNA to be more prevalent than a -NAO for 6”+ storms.

——————
Charlotte and Atlanta won’t be much different. I already checked Atlanta years ago and found similar results favoring +PNA over -NAO.

My definition of neutral is -0.25 to +0.25

@NCSNOW
Thanks for checking. One thing obviously to keep in mind with the NC State climate office study is that it includes all types of winter weather, including significant ZR and or IP which would include a number of CAD winter storms that we’ve often seen with just the benefit a stout -NAO. It does seen though that a +PNA is favored to get a big dog in NC
 
Interestingly, looking back at my two tables of big storms, the last 6 (2014-18) were all with a moderate to strong +NAO!! So, there hasn’t been even one 6”+ snow at either RDU or GSO with a -NAO (even a weak one) since way back on 12/26/2010!!
That is interesting. I thought for sure that both the second storm in January 2018 as well as December 2018 had -NAOs.
 
Someone jog my memory without having to dive deep into past Forums, but the last disruption of the polar vortex happened in December of last year right? then we had the few week lag period which gave us the active Winter storm pattern in January. But the actual event happened in the December correct?

Also, how well did guidance forecast the disruption last November for December?
 
That is interesting. I thought for sure that both the second storm in January 2018 as well as December 2018 had -NAOs.

Actually, all 3 big SE winter storms in 2017-8 had a +NAO. Regarding the two in Jan, here’s the Jan 1-18, 2018 NAO:

2018 1 1 0.502
2018 1 2 0.743
2018 1 3 0.871
2018 1 4 0.725
2018 1 5 0.152
2018 1 6 0.023
2018 1 7 0.233
2018 1 8 0.288
2018 1 9 0.199
2018 1 10 -0.004
2018 1 11 0.073
2018 1 12 0.569
2018 1 13 1.103
2018 1 14 1.582
2018 1 15 1.667
2018 1 16 1.430
2018 1 17 1.184
2018 1 18 0.964


————
Regarding the 12/9-10/2018 storm, it also was during +NAO:

2018 12 1 0.126
2018 12 2 0.469
2018 12 3 0.740
2018 12 4 0.586
2018 12 5 0.795
2018 12 6 1.294
2018 12 7 1.539
2018 12 8 1.519
2018 12 9 1.066
2018 12 10 0.430


Link to daily NAO:
 
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Someone jog my memory without having to dive deep into past Forums, but the last disruption of the polar vortex happened in December of last year right? then we had the few week lag period which gave us the active Winter storm pattern in January. But the actual event happened in the December correct?

Also, how well did guidance forecast the disruption last November for December?
These are the right questions. I’m curious myself.
 
When we get a SSW, it's no guarantee it effects us. Typically it will take a few weeks before notable effects for us. Cold and active storm track is all we can hope for

Generally in the past I've regarded SSW talk as weenie unicorns that never help us. Since it's happening so early I'm a little curious if that bodes well as that's somewhat unique and new. Usually if the SSW does actually happen (if because many times it doesn't), the cold pops up in Siberia.
 
Generally in the past I've regarded SSW talk as weenie unicorns that never help us. Since it's happening so early I'm a little curious if that bodes well as that's somewhat unique and new. Usually if the SSW does actually happen (if because many times it doesn't), the cold pops up in Siberia.

There’s evidence that it on average provides a net cooling in the E US after a varying lag period. Sometimes it won’t but usually it does to whatever extent, intensity, and length of time.
 
Generally in the past I've regarded SSW talk as weenie unicorns that never help us. Since it's happening so early I'm a little curious if that bodes well as that's somewhat unique and new. Usually if the SSW does actually happen (if because many times it doesn't), the cold pops up in Siberia.
Thing about December is that we have a lot of things on our side right now.

1. La Nina climo
2. La Nina / -QBO
3. Weaker than normal SPV
4. Favorable MJO

All of those favor colder than normal temperatures. The whole month may not average cold, but it would be an upset loss if we don't see a good chunk of it colder than normal

Here's today's SPV zonal wind chart. Can see how the SPV is weaker than normal into late Dec. Hopefully, the more important lower strat at 100 hPa (100mb) is even weaker than what is showing here as that would help promote blocking episodes

Nov 12 Euro Zonal.png
 
In range on the regular Op and Ens runs now too

View attachment 176557

All I can say is look out for late Dec and Jan as that period may be one to remember at least for the cold!

One reason I suspect reversals after mid-Jan are more common than earlier ones is that the means peak ~Dec 31st and then start coming down slowly.

*Edited for correction
 
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