bluewave

Not much outside of the Great Lakes this spring. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=24&which=cd&csector=conus&var=precip&w=rank&p=day&year=2026&month=4&sdate=2026%2F03%2F01&edate=2026%2F05%2F13&cmap=RdYlBu&cmap_r=on&_r=t&dpi=100&_fmt=png

JMA has the current velocity potential and an archive with 5 day to 3 month means. https://www.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html

Yeah, the last Nam upgrade was in March of 2017. It nailed the January 2016 event. Sad to see the SPC HREF go as its ensemble max snowfall was actually pretty good with the split bands west and east of NYC and 20”+ amounts for the February 2026 event. https://www.noaa.gov/media-release/review-of-jan-2016-blizzard-preliminary-snow-totals-validates-dc-measurement The preliminary Central Park measurement will be adjusted upward to 27.5 inches, which will become an all-time snowfall record for New York City when certified by NOAA’s National Centers for Environmental Information. A communication error between the weather forecast office in Upton, New York, and the Central Park Conservancy, which volunteers to take official snow measurements in Central Park, led to an inaccurate preliminary total of 26.8 inches. The snow team found the mistake when reviewing the Conservancy’s logbook.

Big Euro and AI upgrade. https://www.ecmwf.int/en/about/media-centre/news/2026/ifs-cycle-50r1-aifsv2-live A significant upgrade to ECMWF's Integrated Forecasting System (IFS), Cycle 50r1, has gone live today (12 May 2026) alongside an update to the Artificial Intelligence Forecasting System (AIFS v2). Cycle 50r1 introduces a more consistent and integrated approach to forecasting the atmosphere’s interactions with the ocean through fully coupled data assimilation, and improvements to known issues with accurately forecasting sudden, heavy, localised rain. It also brings more advanced representation of waves and sea ice. The update to the AIFS introduces, among other features, ECMWF’s first data-driven wave and snow cover forecasts. Florian Pappenberger, Director-General of ECMWF, said: “This is an important upgrade for ECMWF and for everyone who relies on our forecasts. IFS Cycle 50r1 strengthens our physics-based forecasting system, including through fully coupled atmosphere–ocean–sea-ice assimilation and new ocean and sea-ice capabilities. "With AIFS v2, we are expanding its performance, bringing a new generation of AI forecasting into operation, building on ECMWF’s technical competence, operational expertise and data infrastructure. Together, these advances reflect ECMWF’s commitment to innovation and close co-development with our Member and Co-operating States in delivering better forecasts, increasing the value to society.” Matthieu Chevallier, ECMWF’s Head of Forecast Evaluation, added: “The updates to these systems, being formally announced today, will together provide numerous benefits to users of our forecasts. Alongside the scientific and technical advances in coupled modelling and data assimilation, and innovation with AI techniques, we have responded to users’ feedback, for example, with new products. We look forward to hearing their reaction to the quality and accuracy of our forecasts, and on how it impacts their applications.” Forecasting improvements One of the most significant changes to the IFS introduced with Cycle 50r1 is a better representation of convective precipitation, which causes heavy rainfall and violent thunderstorms but is hard to predict because it occurs at smaller scales. The revised convection and cloud-microphysics scheme will reduce excessive stationary rainfall and, instead, represent more realistically how it moves from the ocean across the land. IFS users will also see the introduction of the new NEMO4-SI³ ocean and sea-ice model, bringing substantial improvements in forecasts and analysis over the marine areas, as well as over 40 new ocean and sea ice-related variables. Key improvements include a more accurate representation of how sea ice affects the power of waves and the interactions between waves and ocean currents, often at play in rougher seas. Other improvements for IFS include improved tropical upper-air temperature and wind forecasts, and improvements to temperature and humidity forecasts around the tropopause. For the Copernicus Atmosphere Monitoring Service (CAMS), one of two Copernicus services operated by ECMWF on behalf of the European Commission, the IFS update will enhance the atmospheric composition and greenhouse gas forecasts. The improvements range from the assimilated observations to aerosols and reactive gases, as well as enhanced input data on human-driven emissions. For AIFS, both the Single and Ensemble versions of the system are being upgraded to version two, with each introducing a new wave component. Eleven wave-related variables are being made available to users, enabling predictions, for example, of when we will experience rougher seas. In addition, the AIFS Single v2 wave component shows substantial improvement in the medium-range skill of wave forecasts compared to the physical model, IFS Cycle 50r1. ECMWF’s first data-driven snow cover forecasts are also being introduced with this upgrade. Again, the AIFS Single v2 forecasts show improved performance compared to IFS Cycle 50r1 forecasts, with the predicted snow cover fraction closer to observations. Victoria Bennett, ECMWF's Head of User Services Section, said: “These new cycles bring improvements to the models and introduce new products that address requests from users. In addition, with IFS, we have now removed the duplication between the old “HRES” single forecast and the Ensemble control and introduced other minor technical updates to reduce complexity. We have worked closely with users during the testing period, and with their positive feedback, we are excited to be making the switch.” All the upgrades to our systems are live with immediate effect.

This is the first that the +30C warm pool near the Dateline made it down to 100m in April with a developing El Nino. Notice how much warmer in all aspects we are than 2023 during the same time. You have to wonder if this continues leading to a slower cold pool formation than we typically see toward the later stages of the El Nino in the Western Pacific. We probably wouldn’t know until next winter whether it could cause this one to wind down more slowly than usual during the spring.

The westward lean is closer to the +ENSO MJO 7 composite with the ridge from coast to coast. But notice how the troughs are weaker in the coming forecast near the Aleutians and Baja. Similar to the weak La Niña this past winter when the ridge out West was stronger than the trough in the East. While it may be too early to draw conclusions about next winter, this would result in a weaker Aleutian Low and possibly a weaker low in the Southeast like we saw in 2023-2024 and 2015-2016 relative to 1997-1998 and 1982-1983.

No surprise that the El Nino is beginning to couple with a westward lean close to the +30C warm pool.

Other stations have done it further back in time with Caldwell being the most recent in 2021. Monthly Highest Max Temperature for CALDWELL ESSEX COUNTY AP, NJ Click column heading to sort ascending, click again to sort descending. 2021 84 90 91 91

It will be interesting to see what the pattern does in June following the mid to late May warm up. So far it appears we are in a pattern similar the warmer 2015 El Niño mid to late May as opposed to the cooler 2023 one. The 2015 analog is showing up on the day 8-14 analog composite. 2015 was a warmer summer here than 2023 was. New York, Climate Division 4 Average Temperature June-August higher ranks warmer with 2010 ranking #131 warmest June-August 2025 73.2°F 120* June-August 2024 74.0°F 127 June-August 2023 72.2°F 103 June-August 2022 74.1°F 128 June-August 2021 73.4°F 123* June-August 2020 74.3°F 130 June-August 2019 73.2°F 120* June-August 2018 73.4°F 123* June-August 2017 71.9°F 97* June-August 2016 74.2°F 129 June-August 2015 73.1°F 118 June-August 2014 71.6°F 92* June-August 2013 72.9°F 115* June-August 2012 73.4°F 123* June-August 2011 73.9°F 126* June-August 2010 75.2°F 131 June-August 2009 70.7°F 64* June-August 2008 72.5°F 108* June-August 2007 71.6°F 92* June-August 2006 73.0°F 117* June-August 2005 73.9°F 126* June-August 2004 70.6°F 62* June-August 2003 71.7°F 94* June-August 2002 72.9°F 115 * June-August 2001 72.0°F 100* June-August 2000 69.8°F 33

Hopefully, the developing El Niño can ease these historic drought conditions across the CONUS.

We lose some aspect of the past climate with every baseline temperature jump. But we have to wait until after the event to see specifically what changes will occur. The first one in 1997-1998 put a 1995-1996 snowy benchmark season out of reach for us. The same for the 1993-1994 record cold with benchmark snows in Central to Eastern PA. It was also the beginning of the all or nothing snowfall pattern which lead to more seasons of 30”+ and 18” or lower. Leading to a significant decline in the 19” to 29” winters which were common place from the 1960s to early 1990s. So every snowy season featured it least one KU benchmark event. The absence of KU events has been a feature of the low snowfall winters. It took around 9 years after that event 1997-1998 event for the warmth to make it to the Arctic leading to the big thickness drop and record lower range we have been in. Then a smaller jump in 2010 shifted the summer temperatures to a warmer base that we have been in. Then the historic December 2015 +13 kicked off the era of significantly warmer winters. Places like DC to Philly haven’t seen close to the cold and benchmark snow of the 2009-2010 winter. Same for the Great Lakes not repeating the benchmark snow and very cold conditions of 2013-2014. Plus the Boston historic snows in 2014-2015. Then the rapid warming of the WPAC east of a Japan following this event eventually leading to the faster Northern Stream of the Pacific Jet and decline in 2020s snowfall for us compared to the record snowy 2010s. We did get a nice bounce back winter in 2025-2026 with the first benchmark KU since 2020-2021 and 2021-2022. Still uncertain how the winter storm tracks will respond following this event. The 2023-2024 jump is most recent with 2 of the warmest winters on record occurring for the CONUS in the last 3 years. Hard to say how long the severe drought pattern which developed across the U.S and Canada following this event will last. It will be interesting to see if this 2026-2027 event can shift the pattern to wetter at least temporarily or shift us back to drier again following the event. Very challenging to do multiyear precipitation forecasting. It took 18 years between 1998 to 2016 for that baseline jump to occur. Then only 8 years between 2016 and 2024. Now all the models are indicating the first time for a +2.1 or greater ONI El Niño only 3 years apart and baseline temperature jump. So for the entire planet we are moving into an unknown zone with such rapid warming occurring over shorter intervals of time.

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.