2025-2026 ENSO

[BlizzardWx]

I don't know if others feel this way, but I get really sick of the PSL interface and just making one map at a time. So I made some code that you can put into google colab. It allows you to set up your parameters via function arguments and you can select a range of years and get individual plots for all those years. It lets you do composite plots too but what I really had in mind was if you wanted to say, look at 50 hPa heights for December for the last 50 years. You can do it quickly. It will just get you 50 maps in like 45 seconds. It's just for Anomaly plots.  I can't guarantee it won't break. But it seemed to work for what I tested. Anyway, I know a lot of you make these plots so maybe this helps somebody. There are some commented out examples at the bottom. 

psl_code.txt

 

With that said, the reason why I made that is I wanted to look at the polar vortex position in relation to the winter. I see two current paths in model guidance. The AIFS camp that wants to keep the PV over Canada and the GEFS camp that moves it further east.  Here are some matches I found.

 

With that said, the group I grabbed for 50 hPa look colder than current guidance for mid month. So maybe my composite wasn't so great or maybe it'll trend colder at some point. Not sure.

 

Looking ahead, the central Canada centered PV case rolls forward to a cold eastern half of the country in Jan-Feb. Not surprising given the analog years I found.

It's similar in the PV-east case, but January is warmer. 

 

 

Maybe this is all garbage. But the thing that has caught my attention is the PV being displaced south over Canada. It just makes the cold more available and its probably why so many of the similar PV years were cold. I am not sure I buy it being as cold as these show to be honest and maybe by late December it'll be different enough that this analysis didn't mean anything. Time will tell of course. 

 

 

[raindancewx]

Canadian update continues to insist on El Nino conditions developing in February at the surface. Likely by January below the surface. Fairly cold winter nationally.

Has the cold look for the North-Central US I've been getting from analogs since Aug/Sept.

My blend from Oct - (2013 x4, 2024 x4, 2018, 2022). Hasn't broken yet. I am expecting a pretty widespread warm up after a cold first 10 days or so - we'll see if that pans out.

[Krs4Lfe]

46 minutes ago, raindancewx said:

Canadian update continues to insist on El Nino conditions developing in February at the surface. Likely by January below the surface. Fairly cold winter nationally.

Has the cold look for the North-Central US I've been getting from analogs since Aug/Sept.

My blend from Oct - (2013 x4, 2024 x4, 2018, 2022). Hasn't broken yet. I am expecting a pretty widespread warm up after a cold first 10 days or so - we'll see if that pans out.

Yes once that trough moves over Alaska in the 2nd week of December, I’d expect some milder air from the pacific to flood CONUS and lead to a moderation of temps and probably a pause in the storminess. Hopefully we can cash in before that happens 

[brooklynwx99]

lol, GEFS capitulating. much lower AO, -NAO signal strengthening too

[bluewave]

The EPS has been handling this pattern pretty well over the last week or so. It has been fairly steady with the MJO 6 500 mb pattern dominating. Longer duration MJO 6 patterns tend to show a poleward shift with more ridging returning to Plains and East after the first 10 days. This matches the moderation the EPS has been showing in the pattern for mid month. So the first 10 days or so will probably be the coldest part of December relative to the means. 

 

 

[GaWx]

 

Cold ENSO Winter: PNA Dec to Jan

-1983-4: -0.31 to +0.97

-1984-5: -1.60 to +1.63

-1996-7: -1.23 to +0.63

-1998-9: -0.09 to +0.16

-2008-9: -1.41 to +0.61

-2010-11: -1.78 to +1.29

-2012-3: -1.01 to +0.55

-2013-4: -0.86 to +0.97

-2016-7: -0.35 to +0.28

-2021-2: -2.56 to +1.01

-2022-3: -0.66 to +0.22

 

-So, ALL 11 -ENSO -PNA Decs since 1983-4 switched to +PNA Jans

-Moreover, the 3 strongest -PNA Decs were followed by the 3 strongest +PNA Jans:

Dec 2021: -2.56; Jan 2022: +1.01

Dec 2010: -1.78; Jan 2011: +1.29

Dec 1984: -1.60; Jan 1985: +1.63

Euro Weeklies and ext-GEFS PNA forecast are both going for a solid -PNA in Dec:

 Based on the likelihood of a -PNA this month, January per the pattern of the last 40 years is likely to have a +PNA.

[EastonSN+]

7 hours ago, brooklynwx99 said:

lol, GEFS capitulating. much lower AO, -NAO signal strengthening too

Loving the end of the EPS run. You can see the ridging in the eastern PAC moving east towards the west coast. 

[GaWx]

Today’s 2 week MJO forecasts: GEFS/EPS agree on longest winter phase 8 in 50 years that starts on Wednesday, even longer than the very long/very cold ones of Feb of 2010, Dec of 1989, and Jan of 1985:

[snowman19]

1 hour ago, GaWx said:

 

 

Cold ENSO Winter: PNA Dec to Jan

-1983-4: -0.31 to +0.97

-1984-5: -1.60 to +1.63

-1996-7: -1.23 to +0.63

-1998-9: -0.09 to +0.16

-2008-9: -1.41 to +0.61

-2010-11: -1.78 to +1.29

-2012-3: -1.01 to +0.55

-2013-4: -0.86 to +0.97

-2016-7: -0.35 to +0.28

-2021-2: -2.56 to +1.01

-2022-3: -0.66 to +0.22

 

-So, ALL 11 -ENSO -PNA Decs since 1983-4 switched to +PNA Jans

-Moreover, the 3 strongest -PNA Decs were followed by the 3 strongest +PNA Jans:

Dec 2021: -2.56; Jan 2022: +1.01

Dec 2010: -1.78; Jan 2011: +1.29

Dec 1984: -1.60; Jan 1985: +1.63

Euro Weeklies and ext-GEFS PNA forecast are both going for a solid -PNA in Dec:

 Based on the likelihood of a -PNA this month, January per the pattern of the last 40 years is likely to have a +PNA.

If December ends up a solid -PNA/RNA month, then there is good evidence you provided for a +PNA January. And if it really does happen then kudos to Ray on his December forecast

@40/70 Benchmark

[GaWx]

Change of GEFS AO/NAO forecasts in just 3 days shows how clueless they can be: is it in this case related to the 11/28/25 major SSW?? I’m asking because similar cluelessness was still the case on the day of the 2/16/23 SSWE:

1. AO

Just 3 days ago (day of SSWE): ~+1 for 2nd wk of Dec

 

Today: ~-1 for 2nd wk of Dec!

2. NAO

Just 3 days ago (day of SSWE): slight +NAO 2nd wk of Dec

 

Today: slight -NAO 2nd wk of Dec

 

@donsutherland1

[snowman19]

@40/70 Benchmark

Looks like your musing that the SPV regains strength back to climo/average (no not above normal strength) was a good one after all
 

 

 

 

 

[GaWx]

27 minutes ago, snowman19 said:

@40/70 Benchmark

Looks like your musing that the SPV regains strength back to climo/average (no not above normal strength) was a good one after all
 

 

 

 

 

 Having a quick restrengthening of the SPV didn’t stop the rest of the winter (through early March) from being cold in these two cases:

2002-3: Jan 17th SSWE followed by avg just 2 weeks later

 

1993-4: Jan 1st very weak SPV followed by just below avg just 2 weeks later and mainly above avg rest of winter: