2025-2026 ENSO

[GaWx]

1. It looks like after quite a negative start (~-0.9 for Jan 1-8), we’re most likely headed toward an ~+0.5 PNA for Jan, which will keep the long streak alive of -ENSO -PNA Decembers transitioning to +PNA Januaries that stretches all of the way back to 1983-4. I’ll revisit this when we get the final Jan #.

2. Well, the models did very well in predicting an obliteration of the old record long met. winter phase 6 MJO, which was 13 days (1/30-2/11/2011): the one this month was 17 days as it ran from Jan 5th through Jan 21st:

@donsutherland1@40/70 Benchmark

[40/70 Benchmark]

43 minutes ago, GaWx said:

1. It looks like after quite a negative start (~-0.9 for Jan 1-8), we’re most likely headed toward an ~+0.5 PNA for Jan, which will keep the long streak alive of -ENSO -PNA Decembers transitioning to +PNA Januaries that stretches all of the way back to 1983-4. I’ll revisit this when we get the final Jan #.

2. Well, the models did very well in predicting an obliteration of the old record long met. winter phase 6 MJO, which was 13 days (1/30-2/11/2011): the one this month was 17 days as it ran from Jan 5th through Jan 21st:

@donsutherland1@40/70 Benchmark

@qg_omegaSee.... +PNA January...like I said, guidance was wrong.

[PhiEaglesfan712]

The 10-year snow drought is over: https://x.com/amarkowitzWX/status/2015592086276313584

[EastonSN+]

If phase 1 in a la nina in February is warm we get there Feb1. Of course there will be a lag.

[MJO812]

1 hour ago, EastonSN+ said:

If phase 1 in a la nina in February is warm we get there Feb1. Of course there will be a lag.

 

[bncho]

On 1/7/2026 at 7:22 AM, 40/70 Benchmark said:

Don't write off early March as a potential prime KU target period....I also can see something pretty substantial in early February.

I mean, this is extremely humbling. Just wow!

[40/70 Benchmark]

33 minutes ago, bncho said:

I mean, this is extremely humbling. Just wow!

The 2020-2021 analog had that....plus, while I didn't include 2014-2015 and 2012-2013 due to ENSO, they were decent analogs. 2014-2015 was an exceptionally strong QBO/solar combo analog...best out there.

[so_whats_happening]

21 hours ago, GaWx said:

That’s interesting about phase 1 during La Niña supposedly being relatively warm based on that source. If I get time (it’s a bit time consuming but I’m interested enough to possibly check it), I’d like to assess this based on actual temps for phase 1 in La Niña. I may check Baltimore.

 For all ENSO combined in Feb, it isn’t at all warm in the E US overall:

 

@so_whats_happening

If you click on the link I provided it is important to note there are not a lot of examples to determine either ENSO neutral or Nina of a solid phase 1 passage in February and the resulting effects. Nino is not there at all which is a bit strange.

If you look at the Nina depiction it is a big cold press into the east based of the 500mb pattern with a follow of warming into the plains which would alleviate much of the east at some point. Do I think it will happen, well I honestly would not be surprised if we relax the cold pattern a bit but im not expecting torch like behavior.

To me it seems the results are more of a mixed bag and could easily be explained by other more prevalent signals such as PDO/ PNA/WPO/ NAO etc. If we do indeed get this SPV split all bets are off into either direction of where we go but one would assume we tend to re enforce the pattern we currently would have leading into the split. 

[bluewave]

The unusually early SSW event leading to the disruption of SPV in late November was possibly caused by an interaction between the record low Arctic Sea ice near the Barents and Kara regions and the -QBO. 

This event seems to have caused key features of the November 500 mb pattern to lock in for the winter. It’s also unusual for some many elements of a November pattern to become amplified and persist into the winter. 

The current activation of the STJ and the recent largest snowstorm since January 2022 for spots in the Northeast  is probably the result of the forcing finally shifting east of the Dateline. 

 

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JD044403

one model, HadGEM3-GC31-MM, has a statistically significant equatorward shift in vortex latitude, deceleration of vortex winds, and increase in sudden stratospheric warmings. Its response is found to be highly state-dependent, significant only in the easterly phase of the quasi-biennial oscillation (QBO). Though we cannot comprehensively conclude why models simulate this range of responses, our analysis does highlight areas for consideration in future work to better constrain the stratospheric response to Arctic sea-ice loss. We explore the role of ensemble size, resolution and basic state, including zonal-mean winds in the polar and midlatitude stratosphere and upper troposphere, as well as the QBO.

 

https://alaskaclimate.substack.com/p/december-2025-arctic-climate-summary

 

For the second December in a row, the Arctic-wide average sea ice extent was the lowest on record in all of the major sea ice analyses. In the National Snow and Ice Data Center analysis, the December 2025 average extent was 11.22 million km², which is about 15 percent lower than the late 20th century December average.

The Barents Sea and Baffin Bay had the lowest December extent on record, and northeast of Svalbard the average pack ice edge was north of 81°N 

November 2025 and December into January 2026  500mb composites