bluewave

Remember, SSWs can also reinforce existing warm patterns rather than lead to a colder outcomes. This seems more likely now since it’s so warm with the historic super El Niño. Think how many times in recent years we had warmer patterns prior to the SSW only for the warmth to continue after the event. 2022-2023 and 2023-2024 were great examples of this.

Probably one of the warmest first weeks of November on record from the Upper Midwest into the Northeast. This makes sense given how extreme this El Niño event has become. Many areas will have 10+ departures for the November 1st through 7th. I just posted in the main El Niño thread how these early SSWs in the past have been associated with the November pattern persisting through DJF. We saw this with the early SSW last November 2025 followed by the general 500 mb pattern repeating and amplifying through DJF. So it will be interesting to see if we are getting an early winter preview this month.

This is only the 4th November with a major SSW event. So our sample size is very small. But all 3 previous events were associated with the general November 500mb North American pattern persisting and gaining amplitude through DJF. This was the case in 2025-2026, 1968-1969, and 1952-1953. Should this pattern repeat again in 2026-2027, then this very warm November El Niño pattern will become more amplified during DJF. It would be interesting to find the specific mechanism associated with the early SSW which lead to the November pattern persisting and amplifying through the entire winter in those years. Since it’s very rare for the November pattern to persist through DJF most years. A few seasonal forecasts last year basically repeated the November 2025 500mb pattern for DJF and it worked out for them. 19 November 1952 28 November 1968 28 November 2025

My focus has been on how much warmer each of the months since May have been exceeding the seasonal long range model forecasts and past developing super El Niño events. We all know with super El Niños is that it only takes one well timed storm with just enough cold to snow to make a late season snowstorm. 1997-1998 was a weaker east based event featuring no MC forcing. We had a very active East Coast storm track. Many lows hugged the East Coast. Several lows also tracked out near the Benchmark. But the very powerful EPAC vortex and STJ never really allowed high pressure to become established long enough over the Northeast. So places like NYC Metro saw many rainstorms and very little snow through DJF. It was actually March which delivered the best snow of the season. But March into even early April during the 1990s was much colder and snowier than the 2020s. March snowfall through the first 6 years of the 2020s is at record lows for any 6 year period on record. So in order to out some snow points on the board around NYC Metro, we would want to do it before we get into March which has become so much warmer this decade. Let’s see what happens. But we would need to get an improvement in the lack of cold high pressure in the Northeast vs 1997-1998 to see better snowfall results.

A very San Diego-like October in the Northeast.

During the end-Permian extinction about 252 million years ago, a supercontinent known as Pangaeaexperienced extreme climate disruptions driven by a 10-year mega El Niño episode. [1, 2] Key Details from Research Duration: Unlike modern El Niño events that typically last about a year, the warmest phases of this ancient event lasted up to 10 years continuously. [1, 2] The Panthalassic Ocean: This multi-year event originated in the vast Panthalassic Ocean (the super-ocean surrounding Pangaea), which was much larger than today's Pacific Ocean and absorbed immense amounts of heat. [1] Volcanic Forcing & CO2: Massive volcanic eruptions from the Siberian Traps doubled atmospheric carbon dioxide (CO₂) from roughly 410 to 860 ppm, collapsing ocean circulation and flattening temperature gradients across the super-ocean. [1] Mass Extinction Impact: The decade-long locking of severe drought, extreme heat, and raging wildfires devastated terrestrial forests, accelerated a global feedback loop, and contributed to the greatest mass extinction event in Earth's history. [1, 2, 3]

The 75° at JFK was the 3rd warmest for October 30th. Data for October 30 - JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. 1961-10-30 79 54 0.10 0.0 0 1950-10-30 77 55 M M M 2026-10-30 75 52 0.00 M M 2024-10-30 73 56 0.00 0.0 0 2016-10-30 73 56 0.15 0.0 0 1971-10-30 72 52 0.00 0.0 0 1994-10-30 70 51 0.00 0.0 0

At this point all we are discussing are potential futures. The antecedent CONUS May through October warmth and the intensity of the ENSO SST warming has been the highest on record for a developing super El Niño. So should this continue through the winter, it raises the potential for a warmer outcome averaged out through DJF than 1997-1998, 2015-2016, and 2023-2024. There also could be monthly variability in terms of the where the warmest departures and strongest 500 mb ridging become established which deviate in ways from those years. So month to month comparisons may vary from those years with the sum total of the DJF average 90 day warmth exceeding those years. We probably won’t know for sure the specific details outcome for each individual month until those months are underway. Also note that the seasonal forecast models from a month or more out significantly missed the magnitude of the warmth. Even forecasts issued during the first week of the month were often too cool. So we may continue to see the models play catch up on the warmth the closer in time we get to the forecast period.

You are a funny guy. The reason that I point out how much warmer things have become is due to the fact that I grew up in a much colder 1970s and 1980s. This is literally a new climate paradigm. Not because I like such a warmer planet. But most people off this forum like a warmer climate since a large portion of the population has been moving to the Sunbelt from the colder regions. But there has been some small shift to this long term trend in the last few years. Numerous posts on how the stratosphere might change the eventual outcome vs the super El Niño. Not meant to single you out since I understand that you were only posting the data. But the super El Niño is a much greater climate driver in comparison. We pretty much knew where this was headed with the record WWBs last spring and the early model shift to a stronger and stronger east based El Niño. So no hopes are going to get dashed since expectations were lowered in accordance to how extreme an east based event this has become. The national and global climate system is much bigger than our local backyards. Last winter was our first both cold and snowy winter in 11 years. The limited area of the cold against the background of the 2nd warmest CONUS winter on record explains what has happened. The cold since the 2015-2016 super El Niño baseline shift has become extremely limited. So the chances of any one winter being both colder and snowier than average is becoming less likely. The geographic footprint of the cold when it does occur is more limited. So this new pattern made it possible for us to go this long before experiencing a colder winter. In the old days it was possible to get coast to coast widespread cold. So our chances for a colder winter in any given location were greater. These days we can’t get a colder winter winter in a portion of the CONUS without a much more impressive warm winter somewhere else. We were discussing snowfall before last winter and during previous winters. I was very happy to get the benchmark storm track back for the first time since 21-22. But it highlights how important the benchmark track is for our snow especially since the mid-90s. In the colder climate prior to the mid-90s, we could nickel and dime our way to normal snowfall especially around NYC Metro. It was possible during the colder era to have an average snowfall season with just small or moderate events. But for the last 30 years getting a KU benchmark storm has become a prerequisite. This has lead to the snowfall for places around NYC to become an all or nothing proposition with hardly any more seasons near the mid-20s average. I also said in earlier years that it would be a struggle to get another 50” snowfall season in NYC with how warm the winters have become. Since NYC proper needs a winter close to 32° in order to pull this off. The colder temperatures are necessary but not always sufficient like we found out last winter. Areas like Islip to the east and Newark to the west don’t fall into this category which I also pointed out years ago. So it’s more of a NYC and surrounding stations like LGA and JFK requirement.

The surface warming across the Northern Hemisphere going into November with this historic El Niño is more impressive than what is happening in the stratosphere.

Our area got the warm and dry San Diego weather this month while they got all the rain with the historic super El Niño.

The ridge across the CONUS In October 2026 has been much stronger than 1997. So we didn’t get the Southeast trough this month that 1997 had. It’s why this was one of the warmest Octobers on record across the CONUS vs the much cooler 1997. The North Pacific low was also focused further south near Southern California snd the Baja. Also note the flip of the North Pacific pattern associated with the record warm pool from Japan to North of Hawaii. So this lead to the reversal of the WPO to positive this month rather than more negative in 1997. The strongest ridge axis in the Upper Midwest is making an earlier appearance. We usually have to wait until the winter for this El Niño ridge to emerge.

The lag interval for surface effects from minor and major stratospheric warming events can be quite variable. We had a minor warming event in late December 1997 into early January 1998 and a strong Greenland blocking pattern emerged in January. But since the Pacific vortex was displaced so far to the east, it resulted in a very warm pattern over North America.

My guess is that all these stratospheric disruptions in recent years are linked to the Kara-Barents Seas warming and loss of sea ice there. Many recent studies how focused on this region. Notice how in most of the recent summers the Pacific side has done better than the Atlantic side. While the Pacific side enjoyed the coldest start to summer in a while this year, there was record breaking warmth with low sea ice on Barents and Kara areas. So we have had quite a run of SSWs and weakened vortices since 2020. The successful SSWs and weaker PV for winter weather fans were in January 2021 and November 2025. These events were able to get the Pacific to back off. Even though it took nearly three months following the November 2025 weak PV in late February for our first KU in four years to finally click. Fast forward to the disruption of the PV in February 2023 and we saw the disappointing result of what such an overpowering Pacific leading to the Baja trough that winter could do. Next up were the twin SSWs in January 2024 and March 2024 during our last weaker super El Niño. But we saw quick snap backs of the PV following those events with the very hostile Pacific continuing. Now this early PV disruption is forecast to have a quick rebound. So it’s quite possible that we see another weakening sometime from January to March. But with such an extreme east based El Niño, it’s an open question how much success it will result in. Since it could very well follow the 2024 quick rebound script. https://www.climate.gov/news-features/understanding-climate/understanding-arctic-polar-vortex How Barents Sea Ice Affects the Stratosphere Heat and Moisture Flux: When sea ice retreats in the Barents-Kara Seas, open water exposes the relatively warm ocean to the atmosphere in autumn and early winter. This releases extra heat and moisture. [1] Planetary Wave Enhancement: The added heat creates local thermal anomalies that alter lower-atmosphere pressure patterns. This change enhances upward-propagating planetary waves (Rossby waves) from the troposphere into the stratosphere. [1, 2] Vortex Disruption: When these energetic waves break in the stratosphere, they deposit momentum and heat, weakening or distorting the high-altitude circumpolar winds known as the stratospheric polar vortex. In extreme cases, this triggers an SSW, where stratospheric temperatures jump tens of degrees in just a few days. [1, 2, 3] https://repository.library.noaa.gov/view/noaa/67133 Major sudden stratospheric warmings (SSWs) occur in the Arctic around six times per decade. During winter 2023/2024, two major SSWs occurred – a relatively rare event, having occurred on average only once per decade. Here, we summarise the evolution of the two SSWs, their dynamics and impacts on stratospheric chemical processing and tropospheric weather patterns. While both SSWs were displacement events, they evolved remarkably differently. The 16 January SSW was short‐lived and did not exert a canonical influence on surface weather. In contrast, the 4 March SSW followed a more typical evolution, albeit with only weak coupling to the troposphere.

I only posted the highest peak departures during each of those months. Numerous surrounding stations were also over +10. So you are correct that it would probably take hours noting every station to reach +10 or more since 2015-2016. It’s anyone’s guess at this point exactly where the highest monthly departures will occur during the winter months this coming season. 2015-2016 was unique that it combined with the MJO 6 getting the greatest absolute temperatures and departures all the way to the East Coast. But the CONUS record for warmest December set in 2015 was already exceeded twice since then with two years coming very close. December 2021 and 2023 actually had more extensive warmth and greater coverage of the high departures than 2015. Most of the time the highest departures during super El Niño events occur from the Upper Plains into the interior Northeast. Top 5 Contiguous Warmest U.S. Average Temperature December December 2023 39.76°F 131 December 2021 39.34°F 130 December 2015 38.64°F 129 December 2024 38.16°F 128 December 2025 37.83°F 127 DEC…2015….NYC….+13.3 MAR…2016…MOT….+10.5 JAN…2017….BTV…..+11.0 FEB….2017….ORD….+10.3 FEB…..2018…ATL….+10.6 FEB….2019…MGM….+10.5 JAN….2020…YAM….+9.8 DEC….2021….DFW….+13.2 JAN….2023….DXR….+12.3 FEB….2023…..SSI…..+9.8 DEC….2023….INL…..+15.8 FEB…..2024….FAR…..+17.5 DEC….2024…..LND…..+11.3 DEC….2025….CPR…..+12.1 JAN….2026….RIW……+10.2 FEB…..2026….LND…..+11.3 MAR….2026….PHX…..+12.5