2025-2026 ENSO

[donsutherland1]

1 hour ago, 40/70 Benchmark said:

Yea, AO and EPO are non-starters if they are hostile. NAO is icing on the cake and more of an insurance element against "what could go wrong".

I agree. The NAO does matter more when one goes farther south in the Mid-Atlantic region especially for the Baltimore-Washington areas, though. 

[donsutherland1]

42 minutes ago, Terpeast said:

Did you make this chart yourself? This is really instructive. Have you by any chance made one for KDCA as well? I suspect that would be even more tilted in favor of -AO.

Yes, I made it. Here it is for Washington, DC (KDCA):

[snowman19]

@Bluewave

[40/70 Benchmark]

5 minutes ago, donsutherland1 said:

I agree. The NAO does matter more when one goes farther south in the Mid-Atlantic region especially for the Baltimore-Washington areas, though. 

Yes, absolutely....more ways to skin a cat, so to speak, in New England.

[bluewave]

1 hour ago, snowman19 said:

@Bluewave
 

Yeah, weaker amplitude MJO through 4-6 than last year which was what I was expecting. The strong amplitude October MJO 4-6 years like 2024, 2020, and 2017 preceded the stronger +PNAs from December into January. The weaker years like 2022, 2021, and 2016 had a lower PNA.

So this fits with my early thinking that this winter will be warmer than last year. But my guess is that there could still be some +PNA intervals but not to the extent of last winter.

Snowfall is a bit more of a wild card. Since the snows were so low winter, it wouldn’t take much for an equal or better snowfall outcome. But that won’t be known until I see the December snowfall indicator. 

I am hoping that we can change up the dominant cutter,hugger,and suppressed Southern Stream storm tracks at least for a few weeks to maybe one month. That will probably be MJO dependent and not known until we get close to the time it starts showing up the medium range models.

 

 

 

[chris21]

7 minutes ago, bluewave said:

Yeah, weaker amplitude MJO through 4-6 than last year which was what I was expecting. The strong amplitude October MJO 4-6 years like 2024, 2020, and 2017 preceded the stronger +PNAs from December into January. The weaker years like 2022, 2021, and 2016 had a lower PNA.

So this fits with my early thinking that this winter will be warmer than last year. But my guess is that there could still be some +PNA intervals but not to the extent of last winter.

Snowfall is a bit more of a wild card. Since the snows were so low winter, it wouldn’t take much for an equal or better snowfall outcome. But that won’t be known until I see the December snowfall indicator. 

I am hoping that we can change up the dominant cutter,hugger,and suppressed Southern Stream storm tracks at least for a few weeks to maybe one month. That will probably be MJO dependent and not known until we get close to the time it starts showing up the medium range models.

 

 

 

Not sure that the magnitude of this MJO pass is set in stone yet. There are many solutions depicting a stronger MJO pass and the models haven’t been exactly locked in on its strength.

[FPizz]

2 hours ago, 40/70 Benchmark said:

Yes. The thing about this stretch is that it has been consistently subpar, but I have avoided any bottom-dweller seasons.....just also missed out on the couple of decent ones. It's been a strong of seasons in the 30s and 40s, save for 2020-2021, which barely snuck above 50".

I've had 2 50" seasons since 2016 (the magic year), 17/18 (53") and 20/21 (51", I'm 37 miles as the crow flies away, so pretty much the same exact climate.  Our snow averages are different by 2").  With some very slight adjustments in storm track (probably less than 20 miles) NYC could have had upper 40s to low 50s in those seasons as well (they had 41" in 17/18 and 39" in 20/21).  I think that is where "luck" comes into play (being the "winner" vs "loser" in snow cutoffs/being in the best banding) and not CC.  

[40/70 Benchmark]

39 minutes ago, bluewave said:

Yeah, weaker amplitude MJO through 4-6 than last year which was what I was expecting. The strong amplitude October MJO 4-6 years like 2024, 2020, and 2017 preceded the stronger +PNAs from December into January. The weaker years like 2022, 2021, and 2016 had a lower PNA.

So this fits with my early thinking that this winter will be warmer than last year. But my guess is that there could still be some +PNA intervals but not to the extent of last winter.

Snowfall is a bit more of a wild card. Since the snows were so low winter, it wouldn’t take much for an equal or better snowfall outcome. But that won’t be known until I see the December snowfall indicator. 

I am hoping that we can change up the dominant cutter,hugger,and suppressed Southern Stream storm tracks at least for a few weeks to maybe one month. That will probably be MJO dependent and not known until we get close to the time it starts showing up the medium range models.

 

 

 

I have considered 2021-2022 as a mismatch season. Yes, the PNA will be lower than last season, which isn't saying much...it was very high. I definitely see similarities to 2021-2022 and 2022-2023.

[GaWx]

 As I showed yesterday, seasons with no H hits on the Conus have shown no notable signal one way or the other for the subsequent winter temperatures. What about the other extreme, winters after seasons with 3+ Conus H hits since 1950?

17 winters: 2024-5, 2020-1, 2017-8, 2008-9, 2005-6, 2004-5, 1999-00, 1998-9, 1989-90, 1985-6, 1979-80, 1971-2, 1964-5, 1959-60, 1954-5, 1953-4, and 1950-1. 

 Here’s their average using climo of 1951-2010: slightly mild but that’s likely a little too warm considering that 3 are post-2010

 What about winters after seasons right at the 2 Conus H hit average since 1950? 13 winters: 2022-3, 2021-2, 2019-20, 2018-9, 2016-7, 2012-3, 2003-4, 1996-7, 1995-6, 1986-7, 1966-7, 1960-1, and 1955-6.

 Here’s their average using climo of 1981-2010: mainly slightly warm to near normal but I’d rather call it near normal overall considering that 1981-2010 climo is slightly too cool being that 6 of the 13 are post-2010 and only 3 are pre-1981

——————

 Also, maps for winters following the 29 seasons with exactly one Conus H hit came out right at normal everywhere.

————————

 So, to summarize the maps for winters following Conus H seasons with 3+, 2, 1, and 0, the differences are pretty small. Thus there’s little signal one way or the other for winter temperatures based on the # of US conus H hits of the prior season.

[Typhoon Tip]

Seeing as some of you spend a lot of time engaged in the ongoing monitoring/analysis and application of ENSO this that and the other ...  this and studies like this may be of interest to y'all

 

https://phys.org/news/2025-10-climate-whiplash-effects-due-rapidly.html

 ( forward,   https://www.nature.com/articles/s41467-025-64619-0 )

 

...In the case of this study above, immediately "precipitates" ( haha) the implication of losing predictive skill - particularly in deference to long lead seasonal outlooks where ENSO is factored, it really severely hinders that usefulness. 

[snowman19]

[brooklynwx99]

4 hours ago, 40/70 Benchmark said:

Yea, AO and EPO are non-starters if they are hostile. NAO is icing on the cake and more of an insurance element against "what could go wrong".

I prefer to think of the AO as general blocking, the EPO as an Arctic cold index (independent on where it's going), the PNA as a modulator on where cold ends up in the CONUS, and the NAO as a big storm modifier, at least for NYC south. very difficult to get a MECS+ without a -NAO down here

i've done research on preloading patterns and the -NAO really has no impact up by you. it's all forced by the Pacific, as you know (see Jan 2022, Jan 2015)

[snowman19]

31 minutes ago, GaWx said:

 As I showed yesterday, seasons with no H hits on the Conus have shown no notable signal one way or the other for the subsequent winter temperatures. What about the other extreme, winters after seasons with 3+ Conus H hits since 1950?

17 winters: 2024-5, 2020-1, 2017-8, 2008-9, 2005-6, 2004-5, 1999-00, 1998-9, 1989-90, 1985-6, 1979-80, 1971-2, 1964-5, 1959-60, 1954-5, 1953-4, and 1950-1. 

 Here’s their average using climo of 1951-2010: slightly mild but that’s likely a little too warm considering that 3 are post-2010

 What about winters after seasons right at the 2 Conus H hit average since 1950? 13 winters: 2022-3, 2021-2, 2019-20, 2018-9, 2016-7, 2012-3, 2003-4, 1996-7, 1995-6, 1986-7, 1966-7, 1960-1, and 1955-6.

 Here’s their average using climo of 1981-2010: mainly slightly warm to near normal but I’d rather call it near normal overall considering that 1981-2010 climo is slightly too cool being that 6 of the 13 are post-2010 and only 3 are pre-1981

——————

 Also, maps for winters following the 29 seasons with exactly one Conus H hit came out right at normal everywhere.

————————

 So, to summarize the maps for winters following Conus H seasons with 3+, 2, 1, and 0, the differences are pretty small. Thus there’s little signal one way or the other for winter temperatures based on the # of US conus H hits of the prior season.

The 20-21 fit Joe D’Aleo’s musing that solar minimums see a bunch of east coast hurricane hits….

[40/70 Benchmark]

1 hour ago, snowman19 said:

 

The drought certainly hasn't been worsening in southern New England.

[40/70 Benchmark]

1 hour ago, brooklynwx99 said:

I prefer to think of the AO as general blocking, the EPO as an Arctic cold index (independent on where it's going), the PNA as a modulator on where cold ends up in the CONUS, and the NAO as a big storm modifier, at least for NYC south. very difficult to get a MECS+ without a -NAO down here

i've done research on preloading patterns and the -NAO really has no impact up by you. it's all forced by the Pacific, as you know (see Jan 2022, Jan 2015)

-NAO can actually be more of a hinderance up here on average....but as we say, there are exceptions. NAO is often more about modulating duration up here. I think the PNA is actually pretty crucial to high-end events, especially south of NYC, but even up here to an extent. Tough to dig enough in the absence of a well placed ridge out by Idaho or there abouts.

[Terpeast]

5 hours ago, donsutherland1 said:

Yes, I made it. Here it is for Washington, DC (KDCA):

Thanks. It’s a bit surprising. If the AO is going to be positive, then we should root for a +NAO instead of -

Wondering if the SE ridge linkage happens more with a +AO/-NAO regime…

[donsutherland1]

9 minutes ago, Terpeast said:

Thanks. It’s a bit surprising. If the AO is going to be positive, then we should root for a +NAO instead of -

Wondering if the SE ridge linkage happens more with a +AO/-NAO regime…

I agree. It's possible that other variables contributed, too, beyond the two utilized e.g., PNA. During the AO+/NAO+ days, 61.8% had a PNA+; for AO+/NAO- days, 56.5% had PNA+.

[MJO812]

https://x.com/weatherwilly/status/1978632840305631546?s=19

Cold Winter outlook

[snowman19]

49 minutes ago, donsutherland1 said:

I agree. It's possible that other variables contributed, too, beyond the two utilized e.g., PNA. During the AO+/NAO+ days, 61.8% had a PNA+; for AO+/NAO- days, 56.5% had PNA+.

Mentioned it earlier, but I’ve noticed a common denominator among all the -NAO’s during the winter that kept “linking up” with the SE ridge/WAR….a New Foundland warm pool

[michsnowfreak]

19 hours ago, raindancewx said:

I've been quite happy seeing the extra moisture this October. A lot of big systems (Lows) are forecast by NE Asia for a while, that's typically consistent with big systems moving through the SW at a 17-21 lead time this time of year. So I do see some support already for an active November. That's implied to some extent with the ACE to ABQ cold day correlation as well. 

I could easily be completely wrong about the winter, but its hard to see a warm winter nationally - I could see it regionally (SE/SW, or both). Serious question - I haven't looked - if you did a difference in proportions test for seasons without a US hurricane hit v. with a US hurricane hit, aren't the seasons without a hurricane hit far colder, or more frequently colder at least? I can't think of many winters following no US hurricane landfall in the US that are very warm, and consistently so.

Absolutely gorgeous autumn day here today. Blue skies, colors have exploded this past week, and a crisp chill is in the air. I dont mind in the least that Im in that bright red on the map...because I know it wont last.

[Daniel Boone]

11 hours ago, snowman19 said:

Over the last several years the New Foundland warm pool has been a precursor to -NAO linking up with the SE ridge/WAR

Yeah, that has occurred more often in later Year's.

[Daniel Boone]

2 hours ago, snowman19 said:

Mentioned it earlier, but I’ve noticed a common denominator among all the -NAO’s during the winter that kept “linking up” with the SE ridge/WAR….a New Foundland warm pool

The Cold pool lends to a 50-50 Low of which stops any linkage. 

[Daniel Boone]

3 hours ago, Terpeast said:

Thanks. It’s a bit surprising. If the AO is going to be positive, then we should root for a +NAO instead of -

Wondering if the SE ridge linkage happens more with a +AO/-NAO regime…

I think the Newfoundland warm or cold pool effects whether or not that linkage occurs as it affects the likelihood, longevity and strength of a 50-50 Low. Maybe, Chuck, Larry or Don will take the time to research that and see what the numbers show irt to that.

[so_whats_happening]

13 hours ago, donsutherland1 said:

At least for NYC, the AO is a bigger factor. Red text=% of days e.g., AO-/NAO-; blue text: % of days in the quadrant with measurable snowfall; black text: percentage of total days with measurable snowfall. This is December-February/winter data.

Fascinating! Really cool chart.

[raindancewx]

This is what Claude told me when I gave it this prompt - the newer versions of Claude are a lot better on pattern recognition than the older versions. 

What kind of winter do you expect in the USA following a September that looks like 2025?

Looking at this 500mb geopotential height anomaly map for September 2025, I can identify several key features that would influence the upcoming winter:

Key Pattern Features:

1. Strong negative anomaly over Alaska/North Pacific (deep purple/blue) - indicating troughing
2. Positive anomaly over western North America (yellow/green) - ridging pattern
3. Negative anomaly over the North Atlantic - suggestive of trough there as well
4. Strong positive anomalies in the high latitudes (around 60-90N over northern Canada/Arctic)

Expected Winter Implications for the USA:

General Pattern:

• This setup suggests a ridge-dominated western US and trough-favored eastern US pattern could persist into winter
• The strong Alaskan trough with western CONUS ridge is consistent with a negative Pacific-North American (PNA) transitioning toward positive or a split flow pattern

Regional Expectations:

Western US:

• Likely warmer and drier than average, especially in the Southwest and Great Basin
• Reduced storm activity in California
• Possible drought concerns

Central/Eastern US:

• Greater likelihood of colder outbreaks reaching the Plains and East
• Increased storminess along the East Coast
• More variable temperatures with periodic Arctic intrusions

Pattern Analogs: This resembles aspects of weak La Niña or neutral ENSO winters with a tendency toward cold East/warm West splits.

The strong high-latitude blocking hints at potential for polar vortex disruptions, which could mean occasional severe cold snaps in the eastern 2/3 of the country.

[raindancewx]

10 hours ago, Typhoon Tip said:

Seeing as some of you spend a lot of time engaged in the ongoing monitoring/analysis and application of ENSO this that and the other ...  this and studies like this may be of interest to y'all

 

https://phys.org/news/2025-10-climate-whiplash-effects-due-rapidly.html

 ( forward,   https://www.nature.com/articles/s41467-025-64619-0 )

 

...In the case of this study above, immediately "precipitates" ( haha) the implication of losing predictive skill - particularly in deference to long lead seasonal outlooks where ENSO is factored, it really severely hinders that usefulness. 

I've been telling you for literally a decade that ENSO has no direct correlation now, nor in the past to what happens in the East Coast for winter. So El Ninos are cold. Some aren't. Same for La Nina. Same for snowy/unsnowy. What is the point of these posts?

[Stormchaserchuck1]

28 minutes ago, raindancewx said:

I've been telling you for literally a decade that ENSO has no direct correlation now, nor in the past to what happens in the East Coast for winter. So El Ninos are cold. Some aren't. Same for La Nina. Same for snowy/unsnowy. What is the point of these posts?

Going back to the 1800s, the SOI has a strong correlation with Winter PNA state

https://data.longpaddock.qld.gov.au/SeasonalClimateOutlook/SouthernOscillationIndex/SOIDataFiles/MonthlySOIPhase1887-1989Base.txt

[Stormchaserchuck1]

5 hours ago, Daniel Boone said:

I think the Newfoundland warm or cold pool effects whether or not that linkage occurs as it affects the likelihood, longevity and strength of a 50-50 Low. Maybe, Chuck, Larry or Don will take the time to research that and see what the numbers show irt to that.

I don't know if I trust the validity of that graph to be honest.. it looks like the greatest bunch is weighted toward +NAO/+AO and DC is 39N latitude.. counter-intuitive. +NAO's are wetter. There is more precip, but I think a place so sensitive to the freezing point would be heavily weighted toward -NAO/-AO periods.. I know during my lifetime it hasn't snowed a lot when the NAO and AO have been positive. 

Pacific overwhelms the Atlantic though. Anomaly-wise W->E is actually greater than N->S. 

I've found the New Foundland warm/cold pool has a strong correlation with the Winter NAO in the preceding May-Sept, but not so much the day of. Maybe it has something to do with subsurface currents. 

[raindancewx]

I've never understood the fixation with the PNA for you guys - its completely irrelevant for temps for the parts of the East where snow is heavily dependent on exact temps in big events. Storms and precip and patterns - sure. But who cares if you get storms if you can't determine the temp pattern from it? Its a pattern that matters for the NW and SE US, for temps in winter not the NE and SW US.

These maps by the way show r, not r-squared. So anything below the 0.3-0.5 even for a long period of time is inherently unreliable. So I agree on the ENSO --> PNA relationship, but the point still stands - its not a big deal for the East where you guys live for temps in winter. Using Enso to predict PNA state is fine I guess but it just doesn't tell you much in the East in winter and hasn't ever really.

 

[Stormchaserchuck1]

PNA is a big deal in January

The biggest thing with PNA is its high sea-level pressure correlation on the coast, about +0.5. That's our benchmark storm or not. But yeah, in some other Winter months especially December and March the PNA correlation nears 0. EPO is by far the greatest pattern for temps in the NE 1/2 of the US. I was looking at SOI matches to SE ridge/NW trough before 1948, since that's when the global climate maps started, and it's a strong SE ridge/NW trough correlation with SOI pre-1948.