bluewave

If you were following the seasonal forecasts last November, then you would have seen the ones keying in on the early stratospheric warming and easterly QBO influence warming were on the right track. But it took about 3 months to finally deliver the big KU event. Would have been nice if we didn’t have to wait 11 years for a both cold and snowy winter in what has become a sea of warm. https://opensnow.com/news/post/november-update-2025-2026-winter-forecast-preview

2009-2010 was a much weaker modoki compared to the 2023-2024 full basin event and what 2026-2027 is projected to be. Plus it occurred back in a much colder climate prior to the baseline temperature jumps in 2015-2016 and 2023-2024. This is why places from DC to Philly haven’t experienced anything close to those snowfall totals since.

Your local area has just finished the warmest 11 year stretch of winters into March following the big warmer shift in 2015-2016. Since the winters have still averaged below freezing, it still feels cold. But just not as cold as it had been in the past. So every local area has been affected to varying degrees by this warmer shift. This is why global and national temperatures are important since it shapes which will be felt locally. Places closer to the East Coast that have seen their averages climb to the mid to upper 30s over this period have definitely have felt warmer. It’s why this past winter felt so cold. This winter would have been closer to average in the old days. But relative to the post post 2014-2015 period it felt much colder even though many areas saw no record cold this past winter. It was great to see a return of the benchmark snowstorm tracks which had been absent for the past 3 seasons. The Detroit average 11 winter temperature through 2026 is 30.3°. The previous warmest 11 year stretch had been 28.9° ending in 1957. The earlier arrival of spring over this period resulted a 32.6° December through March average vs the previous highest 31.0° max in 2007. The biggest benefit of these warmer run of winters has been in the lake effect snow favored areas like Marquette. Warmer falls into winters boosted the Great Lakes temperatures and slowed the arrival of ice. So a great set up if you are a big lake effect snow fan.

The sensible weather in any given location is a function of the global temperatures which sets the range of options. It’s why the CONUS winters have shifted so much warmer after 2014-2015 compared to before. This is why your area in the Great Lakes hasn’t been able to experience a repeat of the 2013-2014 winter following the big global temperature jump in 2015-2016. Same for Central and Eastern PA not being able to experience a repeat of 1993-1994 benchmark for snow and record cold. Along with NYC Metro not seeing anything close to 1995-1996. It’s no coincidence that those two benchmark winters occurred before the first big temperature jump in 1997-1998. The climate state from 1997-1998 to 2014-2015 also produced benchmark winters for Boston in 2014-2015 and DC to Philly in 2009-2010 which haven’t been able to be replicated. Following the 2023-2024 temperature shift to warmer weather we experienced the #1 warmest winter and #2 warmest winter for the CONUS only two years ago apart. Even a relatively small temperature shift to warmer in the 1980s hasn’t allowed a top 10 coldest CONUS winter to happen again like we had in the 1970s. So every temperature jump has resulted in some aspect of the prior climate not being able to occur in the new warmer one. But we usually have to wait until after one of these jumps to start observing which elements of the earlier climate state haven’t been carried forward into the newer one.

We had a smaller temperature rise with the 80s into early 90s El Niño events since we were just coming out of the cooler climate prior to 1980. The first global first significant temperature jump occurred in 1997-1998. Then the next one in 2015-2016. Followed by 2023-2024. We didn’t find out what the CRCs were until after the events. So it’s going to take some time to know how all the details following this event also. https://www.nature.com/articles/s41467-025-66143-7 Climate regime shifts (CRSs), characterized by abrupt and persistent transitions between alternative stable states in the climate system, pose serious threats to ecosystems and human well-being. Understanding the potential drivers of CRSs is crucial, particularly in a warming world where CRSs are becoming more frequent. Here, using multiple observations and model simulations, we find that the likelihood of CRS occurrence significantly increases in the context of super El Niño events due to their remarkable climate perturbations. This higher probability is detected across various climate elements, such as surface air temperature, sea surface temperature, and surface soil moisture. In addition, we suggest that this boost effect of super El Niño events on CRSs will be greatly amplified under future greenhouse warming. Our findings underscore a deeper and more persistent climate footprint of super El Niño events, suggesting that early warnings and proactive measures are crucial for mitigating their escalating risks.

We will have to wait and see since we aren’t getting the extreme ridge over Canada like we had from May into June 2023 leading to the record air pollution in NYC from the Canadian wildfires. Notice how 2015 started off warmer in June than 2023 which set the pace for the whole summer. A much warmer winter has been a given with super El Niños like 1983, 1998, 2016, and 2024. But we did find a way to get a generally warmer summer in 2015 than 2023.

Looks like a gradual warming later in May following this coming cooler period. One thing to watch will be that we have a record +PMM now which is closer to the summer of 2015 El Niño than 2023 which didn’t have the strong +PMM. So it’s possible we get a warmer summer than 2023. But we would want to see how the transition from late May into early June verifies in order to know for sure. Stronger +PMM in summer of 2015 Weaker PMM in 2023 EPS forecast next 15 days

There was a recent paper released on this topic calling it the PCC. But we will probably need the data for this next event included to help develop the new idea. Remember, the climate models missed the sudden rise in temperatures in the spring of 2023. So it’s possible that the current climate modeling technology is developing too slowly to capture the faster changes that have been occurring. https://www.nature.com/articles/s41467-024-52731-6 Much recent work focused on whether equatorial Pacific cooling over past decades is driven by anthropogenic effects or arises from internally-generated climate variability, like the IPO. A definitive anthropogenic link to the recent trends would allow us to reliably predict a cooler tropical Pacific. As the tropical Pacific is known to be a climatic pacemaker, for (at least) the near-future this would mitigate global warming via ocean heat uptake and low-level cloud feedbacks. Instead, if the cyclic IPO dominates the recent cooling, we may expect a strong warming when it reverses. In support of the first possibility, we have identified an emerging climate change signal in the tropical Pacific across different observational datasets and we call it the PCC. The PCC has distinctive ocean-atmosphere dynamics that differ from those associated with the IPO. We further demonstrate that the recent trends during the satellite era, which have been the focus of significant attention, result from a combination of IPO and PCC. The emerging PCC SST trend pattern features a narrow band of cooling in the eastern equatorial Pacific and warming elsewhere. This SST change is linked to thermocline shoaling/SSH decreases in the central-to-eastern Pacific and dipole-like changes in zonal surface wind stress. In contrast, the recurrent IPO-driven SST trend pattern is characterized by a meridionally broader cooling in the eastern Pacific, zonal dipole-like thermocline/SSH changes and an overall strengthening of tropical Pacific zonal wind stress. We have shown that these distinct ocean circulation changes are a response to different wind stress patterns. These oceanic responses account for surface cooling in the eastern Pacific, with the thermocline shoaling playing a dominant role in the PCC cooling and enhanced zonal advective cooling mainly driving the IPO-related cooling. While basic geophysical fluid dynamics proved sufficient to attribute the observed oceanic changes to surface wind stress, we have not addressed the origins of the wind stress patterns associated with the PCC and the IPO. New research is needed to elucidate the wind changes, but our leading hypothesis is as follows. In response to GHG forcings39,40 temperature change in the upper troposphere are stronger than at the surface (Fig. S4), increasing atmospheric static stability. Consequently, the initial SST and surface wind response to rising GHGs might not be amplified as efficiently via Bjerknes feedback as is that for the internal modes on interannual to decadal timescales. Given the differences in thermocline and ocean current patterns associated with the PCC and the IPO, the coupled feedbacks related to ocean dynamics are also expected to differ, potentially contributing to distinct climate pattern formations for decadal variability and climate change. Additionally, climate variations outside of the tropical Pacific may influence the tropical Pacific trade winds26,27,41,42,43,44. Further, it has been argued that pronounced decadal-to-multidecadal SST variability in the Atlantic Ocean is also dominated by the response to the same external forcing that the tropical Pacific encounters45. Perhaps the co-occurrence of these long-term trends in different regions is not simply a direct response to rising GHGs but is influenced by inter-basin interactions. More work is needed to disentangle causal relationships among the long-term changes in different basins46,47. Throughout this paper we have taken for granted the widespread assumption that the IPO is an internal mode of the climate system. However, while we worked to distinguish between the recurrent IPO-related decadal variability and the emerging PCC signal, we are open to the possibility that these two may have become coupled together by anthropogenic forcing. They have much in common: shoaling of the thermocline in the east, enhanced upwelling somewhere in the central-to-eastern equatorial Pacific and an enhanced zonal SST gradient across the equatorial Pacific. It seems reasonable to postulate that if the response to radiative forcing is the emerging PCC pattern seen here, then it could initiate coupled ocean-atmosphere feedbacks that favor a negative IPO state that also has an enhanced SST gradient24. This might explain why the most recent IPO swing has been extreme and robust (Fig. S1b). If so, this suggests that in nature forcing is projecting onto natural modes of variability, while it is not clear whether climate models can reproduce this behavior. A new perspective on how internal variability interacts with the climate change signal will be needed in future studies.

The 365 day running mean never really went into La Niña in Nino 1+2 following the +2.1 ONI event in 2023-2024. Remember we were talking about the anomalous WWBs and warming there last winter during the La Niña which had the record +PNA for a La Niña which was more Nino-like. Seems like the unusual WWBs in EPAC during March 2023 with the rapid warming may be part of a different type of ENSO cycle than we have seen before. So this allowed only 3 years to go by before the El Niño emerged again on track for the shortest return period between two consecutive 2.1 or greater ONI events. We also had the record warming in early 2023 ahead of the usual El Niño lag which wasn’t present. I know most here are focused on next winter. But we don’t have any analogs for such big global temperature jumps only 3 years apart. It’s a big unknown how the details will unfold in regard to weather extremes. Since 2015-2016 happened 18 years after the last big rise in 1997-1998. The record increase in 2023-2024 was only an 8 year gap. Now we are talking only 3 years.

Looks like a fairly active pattern for cold fronts moving through from time to time. Main trough looks to be centered over the Great Lakes. It may continue to be the case that the NW winds behind the lows are more impressive than the actual rainfall totals. We’ll see… Perhaps as we approach late May the ridge out West can push into the Great Lakes and Northeast. But we would want to lose that 50/50 low to have a shot at some extended warmth like we had in March and April.

Central Park and Greenwich Village were very close. So they didn’t adjust the total. You can see the big disparity between Newark and the other surrounding sites before they lowered the Newark total in late March. https://www.weather.gov/okx/20260222_23 GREENWICH VILLAGE 20.4 IN 0230 PM 02/23 PUBLIC CENTRAL PARK 19.7 IN 0700 PM 02/23 OFFICIAL NWS OBS UNION COUNTY... NEWARK AIRPORT 27.2 IN 0700 PM 02/23 OFFICIAL NWS OBS 1 NW CRANFORD 21.0 IN 0157 PM 02/23 TRAINED SPOTTER 1 SSW WESTFIELD 20.0 IN 0114 PM 02/23 PUBLIC 1 NW FANWOOD 19.5 IN 0700 AM 02/24 COCORAHS SPRINGFIELD 19.3 IN 0230 PM 02/23 PUBLIC CLARK 18.5 IN 0900 AM 02/23 COCORAHS 1 SSE SPRINGFIELD 17.0 IN 0600 PM 02/23 PUBLIC HUDSON COUNTY... 1 WSW HOBOKEN 23.0 IN 0800 AM 02/24 COCORAHS KEARNY 21.5 IN 0100 PM 02/23 EMERGENCY MNGR HOBOKEN 20.5 IN 0300 PM 02/23 TRAINED SPOTTER HARRISON 18.0 IN 0800 AM 02/24 COCORAHS

You know it’s going to be a big event when they have to adjust the scale higher.

The Euro is coming in stronger with the El Niño following the near record upper ocean heat for so early in an event. It still maintains the warm pool east of Japan. But it also has a very strong +PMM. So maybe the PDO will be in the negative to perhaps neutral range. But probably not the strong +PDO of 2015-2016 and 1997-1998. Right now it looks like the floor for this event is 2.1 to 2.4 on the ONI. The ceiling could be above 2.5 to maybe closer to 3 like we saw back in 2015-2016. Will probably depend on how strong the WWBs are from the summer into the fall. +PDO pattern

Thanks for pointing this out. There was some talk on social media that the total was being reviewed since it was higher than the other surrounding sites. The same thing happened back in 2016. https://www.facebook.com/danzarrow/posts/blizzard-of-2026-recap-the-numbers-are-in-and-they-have-now-been-thoroughly-chec/1443908300437997/ The historic 27.2" total at Newark Airport does appear on this map, but it is highly suspect when compared to its neighbors - it is being investigated. https://www.noaa.gov/media-release/review-of-jan-2016-blizzard-preliminary-snow-totals-validates-dc-measurement The snow team invalidated the preliminary record measurement of 28.1 inches at New Jersey’s Newark International Airport. The team found that snow was measured hourly instead of the standard procedure of measuring every six hours, which led to an inflated preliminary total. Meteorologists at the National Weather Service will follow a scientific method to determine the accurate total before it is sent to NOAA’s National Centers for Environmental Information for certification. The old Newark snowfall record of 27.8 inches set in 1996 stands. Maximum 2-Day Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 1 27.8 1996-01-08 0 2 26.0 1947-12-27 0 3 25.9 1947-12-26 0 4 24.3 2016-01-23 0 5 24.2 2010-12-27 0 - 24.2 2016-01-24 0 6 23.9 2026-02-23 0 7 22.6 1961-02-04 0 8 22.3 2003-02-17 0 9 21.3 2006-02-12 0 10 20.8 1921-02-21 0 - 20.8 1921-02-20 0

Looks like the warm spots make a run on 87° today.The coolest temperatures relative to the means will be over the Great Lakes and Upper Midwest behind the cold fronts.

Pretty impressive to see the upper ocean heat anomalies this week higher than at any point during the 2023-2024 and 2015-2016 events.

Backloaded season for them. The West is one of those places that needs a great snowpack for water supplies and the ski industry. They are way down in both of those areas. Hopefully, the developing very strong El Niño can deliver for them with better snow in the West next winter. Monthly Total Snowfall for Denver Area, CO (ThreadEx) Click column heading to sort ascending, click again to sort descending. 2025-2026 0.0 0.0 0.2 6.6 6.6 T 10.5 3.4 M 27.3 2024-2025 0.0 0.0 23.3 1.4 13.3 5.5 2.0 2.2 0.0 47.7 2023-2024 0.0 7.5 2.9 1.4 3.6 13.7 9.2 6.3 T 44.6 2022-2023 0.0 T 10.9 13.0 13.0 4.7 5.1 2.2 T 48.9 2021-2022 0.0 T T 4.8 13.4 15.8 13.1 T 2.3 49.4 2020-2021 1.0 4.0 5.0 7.0 3.1 13.5 34.0 12.6 T 80.2 2019-2020 0.0 12.5 13.7 2.8 0.9 16.5 7.5 3.7 0.0 57.6 https://www.denverwater.org/tap/denver-water-snowpack-and-water-supply-update Denver Water’s collection and service areas continue to face severe drought conditions, with historically low snowpack. Denver Water depends on mountain snowpack for its water supply, which serves 1.5 million people in Denver and surrounding suburbs. As a result, on March 25, 2026, the Denver Board of Water Commissioners declared a Stage 1 drought, seeking a 20% reduction in water use to preserve water levels and avoid even stricter mandatory restrictions later this summer. On April 8, 2026, the board approved the implementation of temporary drought pricing, starting with May water use and reflected in June bills, to signal the premium value of water during droughts and help incentivize customers to save water. Customers are urged not to turn on automatic sprinkler systems until at least mid- to late-May, or later if possible. It is not necessary to water grass two days per week in April and the beginning of May; keeping automatic systems off will help save water. Occasional hand-watering may be necessary for trees and shrubs during this time. Keep an eye on the weather and let Mother Nature do the watering when she delivers spring rains. Snowpack and water supply update In Denver Water’s collection system, snowpack as of April 27, 2026, remained at the lowest levels observed in the past 40 years: Colorado River Basin: 18% of normal, worst on record. South Platte River Basin: 2% of normal, second-worst on record. Snowpack and melting conditions are unprecedented, with accelerated melting seen since mid-March. Customers need to save water to protect the supply we have right now. Streamflow forecasts are calling for runoff levels to be 10-40% of normal in 2026. Reservoir storage conditions are below average; while in reasonably good shape for the time being, far less snowpack is available to help refill them. As of April 27, 2026, reservoirs were 79% full, versus an average of 85% full for this time.

Wonder if it will be possible to get some 90° heat and dry conditions around Memorial Day for a change? The last time there was 90° heat was back in 2022 but there was some rain on Saturday. All the other 2020s holiday weekends featured cooler to near average temperatures or rain on at least one of the days. Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2025-05-24 69 50 -6.0 0.02 2025-05-25 71 50 -5.3 T 2025-05-26 75 54 -1.6 0.00 Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2024-05-25 81 63 6.2 T 2024-05-26 84 66 8.9 T 2024-05-27 78 66 5.6 0.33 Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2023-05-27 80 54 0.6 0.00 2023-05-28 80 56 1.3 0.00 2023-05-29 79 59 2.0 0.00 Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2022-05-28 79 66 5.8 0.24 2022-05-29 80 62 4.0 0.00 2022-05-30 91 62 9.2 0.00 Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2021-05-29 52 49 -16.5 0.58 2021-05-30 53 48 -16.8 1.15 2021-05-31 76 51 -4.2 T Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2020-05-23 71 55 -2.2 0.79 2020-05-24 68 53 -5.0 T 2020-05-25 73 56 -1.3 T

The tropical forcing tends to focus in areas where the absolute SSTs approach +30C regardless of the departures getting smaller due to climate change. This is one of the reasons that the forcing was so much further west in 2023-2024 and 2015-2016 than in 1997-1998. But it’s possible that if the RONI remains lower relative to the ONI again like in 2023-2024, we may not get the stronger Aleutian Low development like in earlier El Niños. Same for the trough that usually sets up over the Mid-Atlantic and Southeast which was missing back in 2023-2024. Still too early to tell if the troughs will be weaker again like in 2023-2024 allowing more Southeast ridge development than usual. It may be that if the El Niño gets stronger than 2023-2024 in both ONI and RONI, we get more of a traditional stronger Aleutian Low and low in the Southeast. Plus the warm pool east Japan could influence the jet development leading to weaker troughs also even if the SSTs are outside the 20N to 20S RONI range. Then we have the expansion of the subtropical ridges which could also come into play. Remember, we had a weak La Niña in 2025-2026 and the strongest subtropical ridge near the SW U.S. ever from November to March. So these ridges are becoming more dominant than the troughs.

My guess is that the ultimate peak we see in the fall will probably be influenced by how much WWB follow up we get. The recent models back off a bit for early May. They now forecast the next larger one by mid to late May. Could make the difference between a peak in the 2.0 to 2.4 range vs 2.5+. New run Old run

The all-time Nino 3.4 C record was 29.8C set in November 2015. It will be interesting to see the new Euro forecast in a few days. As the middle of its ensemble mean forecast was fairly close with the 2015-2016 event. https://www.cpc.ncep.noaa.gov/data/indices/ 18NOV2015 23.8 2.0 28.0 2.9 29.8 3.0 30.3 1.7 https://www.ecmwf.int/en/newsletter/151/meteorology/2015-2016-el-nino-and-beyond The 2015/16 El Niño broke warming records in the central Pacific, represented by the NINO3.4 and NINO4 indices. At its peak in November 2015, the NINO3.4 SST anomaly reached 3.0°C, breaking the previous record of 2.8°C set in January 1983. In the NINO4 region, large positive anomalies are hard to achieve because average conditions are already warm. In 2015, the anomaly reached 1.7°C, a substantial increase of 0.4°C on the previous record, set in 2009. SST analyses become less precise going back in time, but the size of the anomalies in NINO4 and NINO3.4 means we are fairly confident that these are record values for the whole of the observational period back to 1860. By contrast, in the eastern Pacific (monitored by indices for the NINO3 and NINO1+2 regions) the El Niño remained below the level of the 1982/83 and 1997/98 events. It must be borne in mind that the anomaly records depend on the reference climate, which in this case is a 30-year climate (1981–2010).

Pretty impressive for Nino 3.4 SSTs to be approaching 29C in early May. This is near the record for so early in the El Niño development. The 30C warm pool is fairly expansive near the Dateline.

Models backing off on the cooler temps they were recently showing to start May. We should make it into the 80s this week on the warmest day. The cooler days should be closer to 60° at the warm spots with 50s in other locations which is an improvement over cooler days earlier in the spring. Looks like the coldest departures will settle in over the Great Lakes with a little warmer near the coast.

It’s interesting that the CFS is also showing a -WPO at least in December.

This was one of our most -WPO winters in years. Maybe it’s related to the warm pool east of Japan extending all the way across to California. When the warm pool was there and we had a cold pool near California it lead to the 22-23 winter and the strong +WPO.