40/70 Benchmark

Yes, intuitively this is correct.....but that mid season SSW outlier group matches this year pretty well with respect to the solar and exact QBO. This is why I hedge towards the mid season SSW....will I be shocked if it doesn't work out? Nope- I do agree with a PV surge in early January after a rather tepid start, which likely concides with a stratospheric reflection event and subsequent +NAO/ poleward Aleutian ridging ala 2001, 2002, 2014, 2018. Probably a pretty warm stretch early in January.

Yes and no....I agree generally with what you are saying, but it's not the warming itself that is prohibitive to having good seasons....it's the western warm pool in-and-of-itself that is the reason NAO blocking hasn't been paying dividends....AKA +WPO. Do me a favor and find a great SNE season that also had a strongly +WPO......you can't find one...not in 1948, and not in 2025. https://psl.noaa.gov/data/correlation/wp.data Extreme +WPO being prohibitive isn't a recent development, but rather the consistency and strength of it is. Since 2016-2017, 2021-2022 is the only -WPO season we have had......the concern is that this is some sort of permanent pattern as a result of CC. While we won't know definitely for another 10 years or so, I am still of the opinion that the globe will find a way to achieve balance, and will wait before seeing otherwise. As for the WPO....we here in SNE can thrive with a modestly +WPO value, as was the case in 2017-2018....and yes, we can still get a -WPO season, as was the case in 2021-2022. That being said, SSTs over the eastern Indian ocean do look supportive of +WPO, but the hope is that more abundant E PAC warmth can counter that in much the same manner that the West warm Pool did with El Nino a couple of seasons back...think Relative Ocean Nino Index https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt Always remeber that NOTHING operates in a vacuum, so don't obsess too over any single point on the globe, as ultimately it is not what is going on at said point that is paramount, but rather what is going on at said point relative to the rest of the globe.

Now, one could argue that the character of La Nina isn't important since it's so weak, which is true.....then you would have to default to this: Solar Max/E QBO (2025-2026): The Holton-Tan relationship applies early on given that PV disruptions are likely in December, before the relationship reverses and they are less likely later in the season. The final warming is of course the exception to this rule, while it is usually more relevant for spring, it can and does sometimes occur early enough to have an impact for the major population centers in terms of late season cold and/or snowfall. Below are a couple of annotations to aide in the simplification and visualization of these relationships. Interestingly enough, although statistically speaking early and late season disruptions are favored, there is a an outlier set of major PV disruptions noted in the solar max/E QBO quadrant of the chart above. This also becomes a theme when comparing the solar QBO analog composites. Here is a list of cool ENSO/ solar analogs for the winter 2025-2026 season. Here is a DM composite of these seasons. There are obvious similarities between the Solar composite (right) and the QBO composite (left) given that they both feature high latitude blocking and poleward Aleutian ridging. The primary difference is that the QBO analog composite is biased more towards early and late season NAO blocking, whereas the solar composite focuses the NAO blocking more in the early portion of the season. The discrepancy is primarily with respect to late season owed to the aforementioned outlier set of mid winter PV disruptions, which is evident in the list of SSW analogs compiled from the solar and QBO composites, respectively. January 17, 1971: PV Split December 4, 1981: PV Displacement February 11, 2001: PV Split January 2, 2002: PV Displacement February 22, 2008: PV Displacement January 7, 2013: PV Split February 14, 2018: PV Split March 20, 2025: PV Displacement The majority of the SSW events are split between the mid winter months of January and February with three events per month. There is also an outlier event in December, 1981 and March 2025. The primary analog events of January 17, 1971 and February 11, 2001 were both accompanied by PV splits and are the only two members to appear in both of the QBO and solar analog composites, which lends more credence to the mid winter outlier scenario that contains 6/8 the analogs. Thus the favored timeframe for a SSW and subsequent split of the polar vortex is during the January 14 to February 14 timeframe, which favors late season NAO blocking to commence roughly between February 8 through March 6.

Not much has changed in the September update: The persistence of this regime is generally supported by the consensus of guidance, which is perhaps slightly more supportive of an eastward leaning basin-wide event by winter, as opposed to a bonafide east-base event. This is perceived to be a rather trivial discrepancy, especially given the modest strength of the ENSO event. The newest El Niño Modoki Index (EMI) guidance from JAMSTEC has also remained fairly consisted in it's depiction of an EMI value of around -.20 to -.30 during the boreal winter season. This range is similar to the EMI analogs of 1995-1996, 2017-2018 and 2021-2022, which is supported by the similarity in both the placement (near 140 longitude) and the intensity of the respective subsurface cold pool analogs relative to 2025.

Weak, East-Based La Niña Impact on Extra Tropical Pacific The expectation for both a weaker and east-based La Niña influence during winter 2025-2026 remains consistent with earlier analysis this summer. Note that the behavior of the subsurface during the month of August was anticipated quite well last month, and continues to set the stage for an eastern biased event centered around 120 degrees longitude. Historically speaking, in east-based La Niña winter seasons there is both a high latitude blocking signature and a prevalent poleward Aleutian ridge displaced to the northwest, off of the west coast of the CONUS relative to the central-based and Modoki La Niña composites. These are shared features with the weak La Nina composite, which is similar due to the fact that the majority of east-based events are also weaker cool ENSO episodes . Thus it is not surprising that the composite of the three primary El Niño Modoki Index analogs of 1995, 2017 and 2021 were all centered in the vicinity of 120 West longitude, and 2/3 were weak events; with the 2021-2022 La Nina representing the lone moderate season. Nor is it a shock that the pronounced Aleutian ridging positioned off of the coast and protruding poleward in conjunction with some degree of NAO blocking is also very evident.

Here is +QBO: While it looks like the ridge is a bit more poleward in this composite, I def. don't think it looks flat in the other one. I would say it has more to do with the type/intensity of cool ENSO than it does QBO. Def. more NAO blocking in the Easterly QBO composite.

Here is a composite of seasons since 1950 that I would consider to be cool ENSO and fully Easterly QBO at botht he 30mb and 50mb levels throughout the vast majotiyy of the winter DJFM season....not extremely poleward, but I wouldn't consider that Aleutian ridge to be "flat":

Yea, obviously the point isn't to expect a record winter, but rather we shouldn't be resigned to another dud because the year has been dry thus far.

This is fair....TBH, I struggle to see the connection either, but there is a pattern evident in the composites.

Well, I've showed you the composite, and it simply isn't true. False. Whether it's a coincidence or not, there is also a clear tend in the ACE composites.

Okay, care to acknowledge the other five factors I mentioned?

I don't agree. I can't find on piece of data that argues against it...don't mean it will necessairly work out, but I the point is I see. no reason to bet against it....polar analogs, weak, basin-wide to east-based La Niña, strong E QBO/near solar max, normal to above average ACE.....name it.

I think about 125 ACE and up is considered above normal.....so add another feather in the cap of poleward Aleutian riding this season if that indeed comes to fruition.

Yea, no harm.....happens to all of us. I admire that you put yourself out there.

Oh, Paul Roundy...wow. You're in good hands.

This is what I was saying.

We probably won't indentify it until we see the whites of the snow.

@weathafella

Also, remember...SSTs are part of a feedback, which is the reason for the correlation, but they don't run the show....if the atmosphere begins changing, the sea will not lead the way.

I don't think 2020-2021 was below normal there. 2021-2022 may not have been, either.

They have been for the past several years, and the WPO averaged negative without a NE warm pool to offset in 2021-2022. Anyway, I'm not arguing it's going to make it negative...just prevent it from being extremely positive.

Seasonals have it persisting. Remnant of what triple dip? It wasn't there during those three consecutive La Nina events earlier this decade.

I would feel compelled to go through those seasons and check the QBO/solar states. Its going to be difficult to sustained a storngly +AO early on with a strongly easterly QBO near solar max. 1974 and 1979 appear to be decent QBO matches-

This data set illustrates my point about how crucial the WPO will be. All of these seasons except for 1998, which sucked, had a -WPO. Having a favorable WPO leaves much more margin for error, so hopefully the western warm pool is offset enough by the NE PAC warming so that it isn't so extreme this season. A strongly positive WPO leaves virtually no margin for error around the rest of the hemisphere, so if anything else is significantly unfavorable, then most of us are cooked and upside is near normal.

This data set actually has some nice winters for my area...2004, 1993, 1992 and 1960 were great, very good, great and very good. 1974 and 2016 were respectable. 1979-1980 was my lowest snowfall season ever and 1998 sucked. I think I would take this data set over the other one TBH.