2025-2026 ENSO

[Stormchaserchuck1]

Atlantic (NAO) has slight inverse correlation from October to the Winter

Pacific has a pretty strong direct correlation from October to the Winter, a lot of that is around the PDO, which is strongest in Oct out of PNA/ENSO. 

[donsutherland1]

59 minutes ago, michsnowfreak said:

They are very biased towards enso and also biased towards a warmer climate. That is why periods of cold are never seen far out, you will see them grow colder as the timeframe nears. 

I suspect that its seeming inability to see cold anomalies except at shorter timescales has a lot to do with the idea that boundary conditions drive seasonal averages. ENSO, PDO are prominent conditions. The oceans overall are warming. Therefore, the model forecasts are tipped toward the warmer idea more broadly than is realistic. Worse, the coefficients of determination for such variables related to boundary conditions and actual seasonal outcomes are very low. 

These weak relationships reveal that other important factors are involved, including synoptic scale events that cannot be reliably forecast beyond 10-14 days. Some of these additional variables may not yet be known. Synoptic scale events i.e., large snowstorms, Arctic blasts, etc., can have a great influence on the overall seasonal outcomes. Thus, even a warm winter can be much snowier than normal or a cold winter can lack snowfall. On account of these other variables, every La Niña or El Niño event is not alike.

The seasonal models are not yet at a stage where they can even begin to consistently resolve the actual events that ultimately produce the seasonal outcome. A similar situation applies to subseasonal forecasting. Not surprisingly, beyond two weeks, model skill on the weekly guidance largely disappears. There also seems to be a larger deal of persistence in the two week or longer forecasts than what actually occurs.

AI may improve some of these outcomes. But even then, big challenges could still persist. For example, even as some experiments with random forest models have shown a degree of improved skill in forecasting ENSO, those models are constrained by their knowledge base. Hence, when it comes to forecasting extreme events e.g., super El Niño events, they have great difficulty.

Perhaps the combination of AI and quantum computing might produce some significant breakthroughs. But that's still in the future and perhaps a decade or more away, assuming society values science and basic research to make the investments necessary to arrive at that improved state of forecasting. That's an open question in some areas and it will become even more relevant as major states grapple with the costs of aging populations, rising debt relative to GDP, etc., and the trade-offs involved in making budget allocations.

[PhiEaglesfan712]

4 hours ago, roardog said:

I’ll take Nina over Nino every time around here in the winter. Hopefully we do have a “warm” October. It feels like a lot of times a cold October turns into a mild December. Although, that’s  probably due to a cold October being more common in a Nino. A cold October is kind of useless anyway except for chasing the first flakes of the season or some sloppy early season slush accumulation that melts in a few hours. 

Classic case is 2011. That was a cold October, with a snowstorm at the end of the month. Pattern flipped soon thereafter, and it was blowtorch from November through March.

[Mercurial]

9 hours ago, roardog said:

I’ll take Nina over Nino every time around here in the winter. Hopefully we do have a “warm” October. It feels like a lot of times a cold October turns into a mild December. Although, that’s  probably due to a cold October being more common in a Nino. A cold October is kind of useless anyway except for chasing the first flakes of the season or some sloppy early season slush accumulation that melts in a few hours. 

same

[snowman19]

The fact that the EURO is seeing it now speaks volumes. It’s finally showing a La Niña, the last to the party as always with its extreme ENSO warm bias

[snowman19]

Models have completely backed off on any Atlantic tropical threats for the next 2+ weeks. We are starting to approach the point where we are going to have to accept that this may end up being a below normal season (ACE/named storms) despite the La Niña

[bluewave]

17 hours ago, michsnowfreak said:

If most here follow model longterm seasonal snowfall forecasts over anything else, we have a problem . A longterm snowfall model forecast is probably the least accurate thing out there. Temp/precipitation bad enough....but snowfall? Model snow maps are to be taken with a grain of salt 48 hours out, much less 7 months out.

The reason the Euro seasonal snowfall forecast worked out from Philly to Boston is that the storm track matched the seasonal forecast. So it didn’t really matter for the snowfall outcomes that the overall forecast for DJF was too warm. Since the colder conditions than forecast last winter all arrived behind the Great Lakes cutters after the warm storm tracks. 

[PhiEaglesfan712]

39 minutes ago, bluewave said:

The reason the Euro seasonal snowfall forecast worked out from Philly to Boston is that the storm track matched the seasonal forecast. So it didn’t really matter for the snowfall outcomes that the overall forecast for DJF was too warm. Since the colder conditions than forecast last winter all arrived behind the Great Lakes cutters after the warm storm tracks. 

I love how you cherry pick "Philly to Boston". Why not the mid-Atlantic (Philly to DC)? Oh wait, a lot of places there had a higher snow average the last 2 years than in 16-17 to 22-23, so it won't fit your agenda?

[GaWx]

On 9/5/2025 at 4:07 PM, mitchnick said:

Not that it matters at this point, but the monthly temp forecast isn't that bad for the NE. It's pretty rudimentary, but you get the jist of it that the 3 month averages of +1-2C is likely closer to +1 than +2.

 

1. Indeed. The Sept Euro fcast for the NE DJF anomaly is for an avg of only ~+1.8 F.

2. But that is almost as warm as any Sept fcast for the NE DJF of the last 9 with it just slightly colder than 24-5’s ~+2.0 F and near 22-3, 20-1, and 19-20’s +1.8 F.

3. How has the Sept Euro verified vs actual for La Niña in the NE? I’ll look at NYC:

For NYC using 1991-2020 avgs for the 5 Nina winters since 2017-8:

-24-5 ended up -1.4 F vs ~+2F Sept Euro fcast or ~3.4 F colder than Euro

-22-3 ended up +5F vs Euro ~+1.8F fcast or ~3.2F warmer than Euro

-21-2 ended up +1.1F vs Euro ~+0.4F fcast or ~0.7F warmer than Euro

-20-1 ended up 0.0F vs Euro +1.8F fcast or 1.8F colder than Euro

-17-8 ended up +0.2F vs Euro +0.9F or 0.7F colder than Euro

 So, for the 5 Niña winters since 17-8, the Sept Euro turned out to be in F:

3.4 too warm, 3.2 too cold, 0.7 too cold, 1.8 too warm, and 0.7 too warm or an avg of 0.4 too warm