2026-2027 Record-breaking El Nino

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4 minutes ago, mitchnick said:

Once the Niño starts to weaken, there should be a return of the sst warmth back west with the trade's influence increasing. Of course, it won't be overnight, which is why a weakening of the Niño sooner than later improves our chances of decent snowfall imho. 

Absolutely....this is what happens in my composites. The ridges is displaced SE and makes for an awful December, before it lifts northward more into the NAO domain after El Nino peaks and collapses westward.

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Here is a section from my polar domain write-up in July.

 

The most glaring commonality between the QBO composite and both the solar and intense El Niño composites is the pronounced ridging stretching from the northeastern CONUS and into central Canada, which obviously is a rather mild signal for the forecast area in the seasonal mean. However, it has been mentioned on numerous occasions that neither of these winter composites are entirely bereft of high latitude blocking or even shorts bursts of severe winter weather. This is evident in the bifurcation of the composite below.

This is a signal that is emergent among some seasonal guidance.

What is clear is that as El Niño begins to wane and perhaps shift somewhat to the west as the season evolves, the Gulf of Alaska low begins to retrograde, which allows the central Canadian-Northeastern CONUS ridge to lift up into the NAO domain. This mid-to-latter season progression is the crux of the volatility and Modoki-like episode(s) that have been referenced with the respect the overall characterization of the polar domain. The primary risk here for a transition to a significantly colder pattern is that the block is more oriented towards the Eastern portion of the NAO domain, which is especially evident in the more meager El Niño analogs that did not have the very cohesive Gulf of Alaska low that is synonymous with El Niño. 

 

The inference is that the development of the more Modoki like intervals during the second half of the season is contingent on the progression of the mid latitudes of the northern Hemisphere growing more redolent of traditional El Niño as boreal winter ensues, which should take place given the forecast for this warm ENSO event to reach an unprecedented magnitude as Mother Nature gives her best shot at the redistribution of that stagnant west Pacific warm pool. A prime example of the failure of this effort is the earlier referenced MC-oriented El Nino event of 2023-2024, which actually maintained a North Pacific ridge more characteristic of cool ENSO, with a split low on either side. This essentially allowed ridging to persist overt the northeastern CONUS as if it were a cool ENSO season.

However, it has made clear when discussing the implication of El Niño on the polar domain that the developing uber-El Nino event is unlikely to be as biased towards the MC-end of the spectrum as the 2023-2024 event due to it's extreme intensity, and instead end up more akin to the 2015-2016 event, which had a more subdued MC influence and ultimately did indeed boast a bonafide Gulf of Alaska low. 

 

This is consistent with the expectation for the polar domain throughout out the 2026-2027 winter season. Largely void of high latitude blocking throughout the first half of the season before some intervals of a more disturbed polar domain mixed in throughout the second half. This is a theme that is consistent throughout the vast majority of the analogs, which are littered with notoriously wintry periods such as March 1958, February 1983, March 2005 and latter January into February 2016, a stretch which featured the historic east coast blizzard of January 22-24 and the record cold of Valentine's  Day. This shift towards fleeting bouts of  severe winter weather later in the season is consistent with research concerning the behavior of the higher latitudes during the westerly phase of the QBO, which concluded that the polar vortex is less prone to disruption from Sudden Stratospheric Warmings (SSWs) overall, but grows more susceptible later in the season per what is referred to as the Holton-Tan relationship. This is due to the fact that the default direction of the zonal winds in the polar region is from the west, thus a westerly QBO is consistent with this and is thus less likely to lead to disruption, or a complete reversal of these winds in the case of a technical SSW (Holton, Tan 1980), until later in the season if at all. This is largely because it is theorized that westerly winds in the stratosphere inhibit the development of a stronger Aleutian high, which is more conducive to the development of said SSWs that entail the full reversal of zonal winds that subsequently leads to either a splitting or displacement of the PV. The inference here is that although a positive NAO and stronger than average PV are favored in the DJFM seasonal mean per previously referenced research on years descending from solar max and westerly QBO, the shear magnitude of warmth throughout the entire ENSO basin should disrupt the antecedent MC regime enough to allow for at least some transient intervals of high latitude blocking and potentially severe winter weather later in the season, as El Niño peaks and potentially allows the Gulf of Alaska low to retrograde. Research by Gray et al, 2004 elaborates on this complex relationship between the solar cycle and the QBO phase.