2025-2026 ENSO

[donsutherland1]

This morning's preliminary value of the PNA was +0.707. That's the highest the PNA has been since November 20, 2025 when the PNA reached +0.738.  The PNA will remain positive for several more days before it is forecast to go somewhat negative for a short period of time. Afterward, the GEFS show the PNA rebounding. It remains plausible that a regime change (20+ days where the PNA>0 during the January 12-February 11 period or the 30-day period following the end of the recent long-duration PNA- regime) can occur. 

If so, perhaps the best opportunity for a moderate or larger snowstorm in the Middle Atlantic Region or Northeast could be in the January 25-February 15 timeframe. For such potential to be realized, the synoptic pieces would need to become available. So far, the subtropical jet has been largely quiet this winter. Should the forecast strong WWB materialize, that could lead to the subtropical jet's becoming more active across the southern tier of the U.S. some 10-14 days later. Whether that would align during a favorable longwave pattern remains to be seen. 

In the near-term, lighter snows are likely in parts of the Great Lakes Region and Northeast. The lake effect belts could see greater snowfalls, especially as Arctic air could try to get involved next week.

[Stormchaserchuck1]

[anthonymm]

Need a turn around with a KU in late january or february or else we’re not getting to seasonable snowfall. As bluewave said we need a regionwide 12”+ to have a chance at it. To give you an idea of how hard it is to get 25+” now, even if cpark got a 1’ snowstorm and nothing else this winter, they still wouldn’t reach average. 

[PhiEaglesfan712]

31 minutes ago, Stormchaserchuck1 said:

Wasn't something like this happening at this point 3 years ago? How does this compare to winter 2022-23?

[Stormchaserchuck1]

11 minutes ago, PhiEaglesfan712 said:

Wasn't something like this happening at this point 3 years ago? How does this compare to winter 2022-23?

I don't think the pattern is like 22-23, the Strong Nino in 23-24 changed it up, as did the Solar Max starting in May 2024. I can tell that we want to go El Nino.. Not surprising that we might transition pretty fast. The US 500mb composite for this Winter so far is exactly like what it is before El Nino the next year. Here is February

March

[donsutherland1]

54 minutes ago, anthonymm said:

Need a turn around with a KU in late january or february or else we’re not getting to seasonable snowfall. As bluewave said we need a regionwide 12”+ to have a chance at it. To give you an idea of how hard it is to get 25+” now, even if cpark got a 1’ snowstorm and nothing else this winter, they still wouldn’t reach average. 

Historically, about 30% of winters with similar or less snowfall than 2025-2026 through January 12th went on to see 25" or more snow. My thinking coming into this winter was 15"-25". I still think that's realistic. In any case, here's the historical data for Central Park.

[TheClimateChanger]

On 1/2/2026 at 11:10 AM, GaWx said:

Dec ‘25 will end up cooler than +3.9F once Dec 29-31 are added. Why? Because Dec 29-31 averaged NN to slightly BN vs 1991-2020 climo overall based on my rough est. That could be as cold as ~30 for those 3 days.

 So, the question isn’t if it will end up cooler because it has to based on the above. The question is how much will it bring down the +3.9. Roughly, you’d be adding a 10% weighting with as cold as ~-1 (based on 1991-2020 anomaly) to a 28 day of +3.9. That would come out to ~+3.4 IF the last 3 days were really -1. If it goes back down to ~+3.4, then it could also end up cooler than 1939, something @TheClimateChangerand I have been discussing. Even if Dec 29-31 averaged near 0 anomaly, that would still bring Dec as a whole down to +3.5, still quite possibly cooler than 1939 in the absolute and definitely much cooler for the anomaly vs appropriate climo for each period as 1939 was >+5.5.

 Also, 2015 may turn out warmer. So, 2025 could come in 6th or so.

 This chart only goes through 2021:

Edit: note that per this chart that 1939 was >+5.5 F vs its climo and 1957 was ~+3.9. So, 2025 anomaly also could come in cooler than 1957’s anomaly.

 So, 2025’s anomaly vs its climo could come in 7th.

Ended up narrowly edging out 1939 for 5th place in the official records. Quite the turnaround, considering the first 15 days of the month were around 1.7F BELOW the 1991-2020 mean, per PRISM's analysis.