2025-2026 ENSO

[40/70 Benchmark]

Here is a snippet from my outlook, which I'm still balls deep in.

So much for the warm pool ending La Nina prematurely.

 

During the month of October, there was some speculation in certain weather circles that La Niña may meet a premature demise owed to an encroachment of the subsurface warm pool from the west.

 

However, Eastern Mass Weather cited the strong Indian Ocean Dipole (IOD), as well as a precedent for a the subsurface cold pool to recover after a retreat to the east during last summer as protective factors against an earlier than forecast peak.

 

 

Comparisons were also made to the subsurface of the 2008, which had similar subsurface warmth on the western flank and still did not peal until mid winter.

 

This has analysis has ultimately proven correct, as the subsurface warmth has reclaimed much of the western flank of region 3.4 and event some of region 4 on the heels of consistent trades bursts

[40/70 Benchmark]

[brooklynwx99]

it's refreshing to see these blocked patterns begin to show up in the medium range. similar stuff happened last year

[dmillz25]

13 minutes ago, brooklynwx99 said:

it's refreshing to see these blocked patterns begin to show up in the medium range. similar stuff happened last year

Hopefully it doesn’t link up with the SER like last year

[donsutherland1]

3 hours ago, GaWx said:

Eric Webb expects a rapid -IOD collapse starting soon, which models are showing the effects of as I showed on their Dec IO SST anomaly maps. He’s expecting El Niño to get started very early, which he said elsewhere could conceivably save Feb from being a mild month (we’ll see):

A more rapid shift towards El Niño is probably the one wild card we could play that would have the potential to significantly alter the outcome of the latter part of this winter/February in our favor (though even then it wouldn't be a guarantee that things would shift favorably even in that scenario).

 

Were the La Niña to collapse prematurely, that would herald the likelihood of warmth in parts of the East in both January and February. Perhaps the best proxy for rapid collapses are cases where the ENSO R3.4 anomaly was -0.50° or below during December and >-0.50° during January. There were only four cases since 1950 that met that criteria: Winters 1951-52, 1952-53, 1974-75, and 2001-02. 

I don't expect this winter to meet such criteria. If so, the coming winter would wind up quite a bit warmer than what I'm currently thinking and also what the latest ECMWF suggested.

[stadiumwave]

10 hours ago, snowman19 said:

It’s showing an east-based -NAO for December 

 

Agree, but my point was last year missed.

[stadiumwave]

43 minutes ago, brooklynwx99 said:

it's refreshing to see these blocked patterns begin to show up in the medium range. similar stuff happened last year

 

Yea, when it's changes that much it makes you think how in the world can you put stock in an 11-15 day output. 

[George001]

13 hours ago, snowman19 said:

Agreed. Unless we see a major SSWE and SPV destruction or close to it, I don’t see how we avoid a canonical La Niña mid-late January and especially February and March

I wouldn’t be surprised if we see a repeat of last Feb with storms taking more of a northern track. I am all in on a big January though. 

[40/70 Benchmark]

26 minutes ago, George001 said:

I wouldn’t be surprised if we see a repeat of last Feb with storms taking more of a northern track. I am all in on a big January though. 

I actually like February better than most of January.

[George001]

15 minutes ago, 40/70 Benchmark said:

I actually like February better than most of January.

I’m not nearly as negative about Feb as many here, but that surprises me. Just curious, what do you think many of us who are less optimistic about Feb are missing? Or are you just less optimistic about January?

edit: I just saw your post raising concerns about the pac jet for January. 

[GaWx]

2 hours ago, donsutherland1 said:

Were the La Niña to collapse prematurely, that would herald the likelihood of warmth in parts of the East in both January and February. Perhaps the best proxy for rapid collapses are cases where the ENSO R3.4 anomaly was -0.50° or below during December and >-0.50° during January. There were only four cases since 1950 that met that criteria: Winters 1951-52, 1952-53, 1974-75, and 2001-02. 

I don't expect this winter to meet such criteria. If so, the coming winter would wind up quite a bit warmer than what I'm currently thinking and also what the latest ECMWF suggested.

Thanks, Don.

Did you mean to include 1951-2 and 1952-3 or are those typos?

[donsutherland1]

4 hours ago, GaWx said:

Thanks, Don.

Did you mean to include 1951-2 and 1952-3 or are those typos?

While those weren’t La Niña winters, I expanded the very limited dataset to include all years with rapid warming of ENSO Region 3.4 from a cool December figure. The response in January and February was the same with or without those two cases.

[chubbs]

The recent flip to NAO- in modeling is positive for this winters snowfall in the northeast. Below is the correlation of November NAO with total winter snow for the La Ninas since 1950. During La Nina, there's a negative correlation of November NAO with total winter snow in the northeast; i.e, negative Nov NAO tends to produce more snow. Also included a plot for Philly to illustrate. 

 

[snowman19]

9 hours ago, 40/70 Benchmark said:

Those enhanced trades in the CPAC are destructively interfering with MJO propagation, which is why it has really slowed down. While I believe it does propagate into phase 6, I have serious doubts as to what happens once it starts getting into phase 7…

[bluewave]

19 hours ago, 40/70 Benchmark said:

My honest opinion that he exagerates some of this stuff moving forwards, but to be fair to him, the jury is still out.

There are no exaggerations involved since its stuff that has already happened. The warmer the seasons get, the more they are falling into these repeating patterns. Both the actual patterns and the model error or bias patterns. It’s a reliable feature for better long range forecasting.

[40/70 Benchmark]

50 minutes ago, bluewave said:

There are no exaggerations involved since its stuff that has already happened. The warmer the seasons get, the more they are falling into these repeating patterns. Both the actual patterns and the model error or bias patterns. It’s a reliable feature for better long range forecasting.

I am referring you the attribution aspect and what it means moving forward, but will leave it at that because nothing constructive will come of it.

[40/70 Benchmark]

7 hours ago, George001 said:

I’m not nearly as negative about Feb as many here, but that surprises me. Just curious, what do you think many of us who are less optimistic about Feb are missing? Or are you just less optimistic about January?

edit: I just saw your post raising concerns about the pac jet for January. 

I think the strat may offer some assistance late season, but if it doesn't, all bets are off. I will posting my thoughts early next week....a great deal of time is spent addressing many of the CC related issues that @bluewaveraises.

[bluewave]

On 11/3/2025 at 7:08 AM, snowman19 said:

The Northeast Pacific continues to cool, the “blob” area has cooled over -1.25C since September 1st. While these SSTs are not driving the pattern, it’s indicative of a longwave pattern that favors cooling in that area. If we get to 11/30 with no sign of this trend completely reversing, it’s going to become very difficult for people to continuing using years that saw SST patterns with a “warm blob”. To clarify, I’m only speaking of the people who are using SST analogs with warm blobs, not other factors (QBO, solar, PDO, AMO, etc.) to justify certain analogs
 

I was commenting on this a while back. That NE PAC warm blob is more a function of the forcing over the WPAC region. It really isn’t a stand-alone forcing or feedback mechanism like the subtropical and tropical WPAC warm pool east of Japan. So we just saw the greatest fall drop since the fall of 2019.

 

[40/70 Benchmark]

3 minutes ago, bluewave said:

I was commenting on this a while back. That NE PAC warm blob is more a function of the forcing over the WPAC region. It really isn’t a stand-alone forcing or feedback mechanism like the subtropical and tropical WPAC warm pool east of Japan. So we just saw the greatest fall drop since the fall of 2019.

 

Yes. I agree with the vast majority of what you are saying.

[bluewave]

Just now, 40/70 Benchmark said:

Yes. I agree with the vast majority of what you are saying.

I guess the big question going forward this winter is if we can at least get one +TNH month like we got last January. Prior to that we had the much more productive one in January 2022.

But that had the great -WPO block which was able to weaken the Pacific Jet along with the MJO 8. Last January the Pacific Jet kept going leading to big Southern Stream storm suppression with the kicker troughs coming in to Western North America.

Then the question then becomes if we do get a +TNH interval, can the jet relax enough for some -WPO blocking in tandem to maybe allow some semblance of a benchmark track to develop for at least a few weeks?

[40/70 Benchmark]

4 minutes ago, bluewave said:

I guess the big question going forward this winter is if we can at least get one +TNH month like we got last January. Prior to that we had the much more productive one in January 2022.

But that had the great -WPO block which was able to weaken the Pacific Jet along with the MJO 8. Last January the Pacific Jet kept going leading to big Southern Stream storm suppression with the kicker troughs coming in to Western North America.

Then the question then becomes if we do get a +TNH interval, can the jet relax enough for some -WPO blocking in tandem to maybe allow some semblance of a benchmark track to develop for at least a few weeks?

Your contention is that the warm pool creates a +WPO pattern that promotes both a western storm track, and a fast jet that knocks down PNA ridges/shears phasing attempts and causes suppression, correct?

[bluewave]

3 minutes ago, 40/70 Benchmark said:

Your contention is that the warm pool creates a +WPO pattern that promotes both a western storm track, and a fast jet that knocks down PNA ridges/shears phasing attempts and causes suppression, correct?

It appears that the WPAC warm pool in conjunction with the cold over Siberia promotes the very fast Pacific Jet along the gradient between the two extremes of warm and cold.

While we have observed the warm pool peak diminishing a bit in magnitude from the summers into winters, enough warmth is retained both on the deep subsurface and the surface to maintain the steep temperature gradient.

I would like to see if we can at least get a few weeks when a -WPO links with a +TNH to know if there is at least some potential to weaken the Pacific Jet enough to allow a few benchmark storm tracks. But we won’t know if it’s possible until we can actually verify a potential weakening of the jet.

[40/70 Benchmark]

6 minutes ago, bluewave said:

It appears that the WPAC warm pool in conjunction with the cold over Siberia promotes the very fast Pacific Jet along the gradient between the two extremes of warm and cold.

While we have observed the warm pool peak diminishing a bit in magnitude from the summers into winters, enough warmth is retained both on the deep subsurface and the surface to maintain the steep temperature gradient.

I would like to see if we can at least get a few weeks when a -WPO links with a +TNH to know if there is at least some potential to weaken the Pacific Jet enough to allow a few benchmark storm tracks. But we won’t know if it’s possible until we can actually verify a potential weakening of the jet.

Absolutely. Makes perfect sense. My guess is that we can, but will have to "make hay", so to speak in reduced intervals of time relative to similar patterns in the past.

[EastonSN+]

10 hours ago, dmillz25 said:

Hopefully it doesn’t link up with the SER like last year

I don't remember it linking up to the SE ridge last year like it did the previous 2 winters. I do remember the board commenting that we were happy to see it disconnected.

The fact that it did not link up helped the Middle Atlantic score a good snowfall winter. Storm track was too far south for us. 

[jm1220]

27 minutes ago, EastonSN+ said:

I don't remember it linking up to the SE ridge last year like it did the previous 2 winters. I do remember the board commenting that we were happy to see it disconnected.

The fact that it did not link up helped the Middle Atlantic score a good snowfall winter. Storm track was too far south for us. 

The problem was that as soon as a ridge would try to get established in the West, the Pacific jet would just knock it down or shove it east which meant storms couldn’t turn the corner in a good place for us and they’d be forced out to sea. We also couldn’t get a well timed phase with so much chaos and shortwaves everywhere. That’s why I’m so pessimistic about our chances especially north of DC to south of Boston with this pattern continuing. I-90 to maybe I-84 can still get good events from SWFE, very rarely down here when everything aligns. The suppressed patterns can help the DC/Baltimore area and south. East of I-81 and north of the M/D line to around the I-84 corridor, we need those benchmark tracks to have a shot at normal snow. We’re in a unique shaft zone here with this new regime. 

[40/70 Benchmark]

4 minutes ago, jm1220 said:

The problem was that as soon as a ridge would try to get established in the West, the Pacific jet would just knock it down or shove it east which meant storms couldn’t turn the corner in a good place for us and they’d be forced out to sea. We also couldn’t get a well timed phase with so much chaos and shortwaves everywhere. That’s why I’m so pessimistic about our chances especially north of DC to south of Boston with this pattern continuing. I-90 to maybe I-84 can still get good events from SWFE, very rarely down here when everything aligns. The suppressed patterns can help the DC/Baltimore area and south. East of I-81 and north of the M/D line to around the I-84 corridor, we need those benchmark tracks to have a shot at normal snow. We’re in a unique shaft zone here with this new regime. 

I agree with what you are saying, but I highly doubt this "screw zone" is permanent...part of the issue has been the lack of cold in SE Canada, which seems to be changing, so there will be more snow indepenedent of BM blizzards.