bluewave

Water conservation measures announced in some localities as the reservoir levels get down to 70%. This has been a top 10 driest fall to fall period across the region. Nantucket has been one of the driest spots with the coastal storms getting suppressed to our south. https://www.wfsb.com/2025/10/03/bristol-mayor-announces-water-restrictions-amid-drought/?outputType=amp

We usually don’t get two mismatch La Niña years in a row. So I wasn’t expecting another one this year. Plus the ACE usually declines in the following years from peak seasons like last year which went 161.

So far we are getting the weaker October MJO 5-6 amplitude from the available forecasts. This is similar to 16-17, 21-22, and 22-23. Last October was the stronger amplitude like 20-21 and 17-18. So we got the much stronger +PNA mismatch from those winters. So the early indicators are this winter will be warmer than last winter was with a weaker PNA than last winter. But there could still be +PNA intervals. Snowfall is tricky since the snowfall was so low anyway last winter. So I don’t have a clear signal yet whether the smowfall will be below, similar to or above last winter. I will refine the snowfall forecast once we see what happens in December. If the areas around NYC are below 4” again like last years December La Niña, then it will be another below average season. The lower ACE this year is also following what we experienced in 2016, 2021, and 2022. Meaning that there was a step down following the higher ACE years like we saw in 2024, 2020, and 2017.

The 1976-1977 winter was a weaker reflection of that one. But it’s still the coldest winter that I have ever experienced. Waiting for the school bus at 7:45 am with temps near 0° and strong winds was a memorable experience. https://www.facebook.com/greaterlongisland/posts/the-great-south-bay-frozen-circa-1976-1977-️-who-remembers-when-you-could-drive-/979944926830556/

There is some data going back to 1779-1780 when we had over 95” here on the CT Shoreline. . The cold and snow that winter set the benchmark for coldest winter of the last several hundred years. So the 1995-1996 winter was only the snowiest in modern times. https://www.nps.gov/morr/learn/historyculture/hard-winter-news.htm William Smith (a loyalist living in New York City) records in his diary that on January 16, 1780, people were walking across the frozen Hudson River from New York to Paulus Hook (today Jersey City) New Jersey. A Hessian soldier, Johann Dohla recorded in his diary on January 30, "The North (Hudson) and East rivers are frozen solid. The ice was checked and found to be eighteen feet thick. All ships were frozen in, and it was possible to cross over the North (Hudson) River on foot, riding or driving, without fear." Later, (on February 22) Dohla wrote "Today the North River ice began to break, after having been frozen for nearly seven weeks." A German officer, Major Baurmeister wrote, "The severe winter covered the North River with ice early in January; even where the current of the river is swiftest, the ice was eleven feet thick, in spire of the fact that it is 1800 yards wide between Fort George (today Battery Park, New York City) and Powles Hook." February 1780 seems to have been even colder: On February 10, William Smith mentions in his diary that a few days earlier a "24 Pounder" (that is, a cannon that fired a solid ball weighing 24 pounds - the entire cannon weighed three tons) was rolled across the Hudson River to Paulus Hook (today part of Jersey City, New Jersey.) Smith goes on to say that even a heavy load as this it made no impression on the ice. On the night of February 10th, Smith heard that four to five hundred British cavalry rode their horses across the river. MANY ACCOUNTS MENTION UNPRECEDENTED CONDITIONS A teacher in Yale College (New Haven, Connecticut) recorded approximately twenty days with snowfall, and a total of 95 inches of snow that winter. People walked across the Sound from Stanford, Connecticut to Long Island. Others walked from Rhode Island mainland to Block Island. Chesapeake Bay and the York River in Virginia froze over for the first time since Europeans settled there. Many people mentioned in letters that they could not remember a winter as bad.

What has happened since 15-16 with the general warming and 18-19 for the warmer storm tracks is not a cycle. It’s a direct shift related to the expansion of the subtropical ridging. This has lead to vast swaths of record SSTs is the mid-latitudes. A farther north storm track than we used to get. So it’s natural in such a pattern for areas that end up south of the dominant storm tracks to experience less snow than we used to get. We have been experiencing a series of gradual shifts since the early 1980s. But the shift that has occurred over the last decade has been the most dramatic. People expect gradual linear shifts when it comes to weather. But the climate system produces non-linear jumps once a certain temperature threshold have been crossed. This new study really isn’t a surprise given the rapid warming of SSTs in North Pacific. But it’s good to see this new attribution technique correct the climate model errors. Similar shift in the North Atlantic so rapidly warming the climate leads to more persistent -PDO and +AMO patterns. https://www.colorado.edu/today/2025/08/14/human-emissions-drove-megadrought-western-us Greenhouse gas and aerosol emissions from human activity have been driving the prolonged drought in the western United States through a complicated connection with the Pacific Ocean, according to a new CU Boulder-led study. For more than two decades, an extreme dry spell has drained the Colorado River, devastated local farms, and intensified wildfires across the American Southwest. The new prediction, published August 13 in Nature, could help water managers region develop better water use plans or invest in infrastructure accordingly, with relief potentially still decades away. “Our results show that the drought and ocean patterns we’re seeing today are not just natural fluctuations—they’re largely driven by human activity,” said Jeremy Klavans, postdoctoral researcher in CU Boulder’s Department of Atmospheric and Oceanic Sciences and lead author of the study. Worst drought in 12 centuries The drought hitting the Colorado River Basin states and California is directly linked to a climate pattern of the north Pacific Ocean, known as the Pacific decadal oscillation (PDO). The PDO is a natural fluctuation of the Pacific that waxes and wanes every two decades or so. In its positive phase, waters in the eastern Pacific Ocean along the U.S. West Coast tend to be warmer, whereas waters near Japan are colder. In its negative phase, the pattern flips, bringing cold water to the eastern Pacific. Since the 1990s, the PDO has been stuck in a negative phase, an unusually long stretch for a typical cycle, Klavans said. That has had profound impacts on the United States. The cold air and water along the U.S. West Coast hold less moisture than warm air, causing a reduction in precipitation. This extended cool phase also pushed storms that would have brought water to the region farther north. As a result, scientists estimated that about 93% of the western United States is experiencing drought, with 70% facing severe dry conditions. Prior studies have shown that the past two decades have been the driest in the American Southwest in at least 1,200 years. Scientists had long thought that the PDO was entirely determined by natural forces, such as the heat exchanges between the ocean and the air. Even the latest report from the Intergovernmental Panel on Climate Change (IPCC), a body of experts convened by the United Nations, said the PDO is controlled by natural forces with high confidence. If that theory was correct, the PDO should have flipped from negative to positive in 2015 after a strong El Niño event warmed the Pacific. Instead, the PDO shifted positive for a short time following the El Niño before reverting to the negative phase again. New reality To understand why the PDO has been stuck, Klavans and his team used a large collection of climate simulation programs to predict what would happen in the future. Using a new suite of over 570 simulations, the team found that between 1870 and 1950, changes in the PDO were almost entirely driven by internal forces. But since the mid-20th century, greenhouse gas and aerosol emissions have accounted for more than half of the variations in the PDO. The team discovered that existing climate models tend to overestimate the role of internal factors on the PDO while underestimating the influence of external factors, such as emissions. After correcting the imbalance, the team found that emissions, and their impacts on the PDO, have been responsible for nearly all of the precipitation decline in the western United States over the past three decades. “People have been trying for a long time to find out why this part of the country is so dry, and we have an answer for that finally,” Klavans said. Because the same imbalance has been shown in other regions, Klavans said the study’s implications could go far beyond the Pacific. For example, the North Atlantic Oscillation, a similar fluctuation over the Atlantic Ocean, is driving drought in places like Spain. He added that improving climate models to capture the role of external forces could help scientists predict future changes in precipitation across the globe. As for the American Southwest, the outlook is grim. If greenhouse gas emissions continue to rise, the PDO will likely remain in its negative phase, and the drought will persist for at least the next three decades, Klavans said. “With this information, water planners could set new expectations and make proper investments in water infrastructure now, knowing this drought is here to stay,” Klavans said. For example, some Californian cities are already building desalination plants to turn seawater into drinking water. “This study can allow us to better quantify the costs of continued greenhouse gas emissions for Americans,” Klavans said. “That can only help our region plan for a better future.” https://www.nature.com/articles/s41586-025-09368-2 This anthropogenic influence was previously undetected because the current generation of climate models systematically underestimate the amplitude of forced climate variability. A new attribution technique that statistically corrects for this error suggests that observed PDO impacts—including the ongoing multidecadal drought in the western United States—can be largely attributed to human activity through externally forced changes in the PDO. These results indicate that we need to rethink the attribution and projection of multidecadal climate. https://www.colorado.edu/today/2025/08/14/human-emissions-drove-megadrought-western-us Greenhouse gas and aerosol emissions from human activity have been driving the prolonged drought in the western United States through a complicated connection with the Pacific Ocean, according to a new CU Boulder-led study. For more than two decades, an extreme dry spell has drained the Colorado River, devastated local farms, and intensified wildfires across the American Southwest. The new prediction, published August 13 in Nature, could help water managers region develop better water use plans or invest in infrastructure accordingly, with relief potentially still decades away. “Our results show that the drought and ocean patterns we’re seeing today are not just natural fluctuations—they’re largely driven by human activity,” said Jeremy Klavans, postdoctoral researcher in CU Boulder’s Department of Atmospheric and Oceanic Sciences and lead author of the study. Worst drought in 12 centuries The drought hitting the Colorado River Basin states and California is directly linked to a climate pattern of the north Pacific Ocean, known as the Pacific decadal oscillation (PDO). The PDO is a natural fluctuation of the Pacific that waxes and wanes every two decades or so. In its positive phase, waters in the eastern Pacific Ocean along the U.S. West Coast tend to be warmer, whereas waters near Japan are colder. In its negative phase, the pattern flips, bringing cold water to the eastern Pacific. Since the 1990s, the PDO has been stuck in a negative phase, an unusually long stretch for a typical cycle, Klavans said. That has had profound impacts on the United States. The cold air and water along the U.S. West Coast hold less moisture than warm air, causing a reduction in precipitation. This extended cool phase also pushed storms that would have brought water to the region farther north. As a result, scientists estimated that about 93% of the western United States is experiencing drought, with 70% facing severe dry conditions. Prior studies have shown that the past two decades have been the driest in the American Southwest in at least 1,200 years. Scientists had long thought that the PDO was entirely determined by natural forces, such as the heat exchanges between the ocean and the air. Even the latest report from the Intergovernmental Panel on Climate Change (IPCC), a body of experts convened by the United Nations, said the PDO is controlled by natural forces with high confidence. If that theory was correct, the PDO should have flipped from negative to positive in 2015 after a strong El Niño event warmed the Pacific. Instead, the PDO shifted positive for a short time following the El Niño before reverting to the negative phase again. New reality To understand why the PDO has been stuck, Klavans and his team used a large collection of climate simulation programs to predict what would happen in the future. Using a new suite of over 570 simulations, the team found that between 1870 and 1950, changes in the PDO were almost entirely driven by internal forces. But since the mid-20th century, greenhouse gas and aerosol emissions have accounted for more than half of the variations in the PDO. The team discovered that existing climate models tend to overestimate the role of internal factors on the PDO while underestimating the influence of external factors, such as emissions. After correcting the imbalance, the team found that emissions, and their impacts on the PDO, have been responsible for nearly all of the precipitation decline in the western United States over the past three decades. “People have been trying for a long time to find out why this part of the country is so dry, and we have an answer for that finally,” Klavans said. Because the same imbalance has been shown in other regions, Klavans said the study’s implications could go far beyond the Pacific. For example, the North Atlantic Oscillation, a similar fluctuation over the Atlantic Ocean, is driving drought in places like Spain. He added that improving climate models to capture the role of external forces could help scientists predict future changes in precipitation across the globe. As for the American Southwest, the outlook is grim. If greenhouse gas emissions continue to rise, the PDO will likely remain in its negative phase, and the drought will persist for at least the next three decades, Klavans said. “With this information, water planners could set new expectations and make proper investments in water infrastructure now, knowing this drought is here to stay,” Klavans said. For example, some Californian cities are already building desalination plants to turn seawater into drinking water. “This study can allow us to better quantify the costs of continued greenhouse gas emissions for Americans,” Klavans said. “That can only help our region plan for a better future.” https://www.nature.com/articles/s41586-025-09368-2 This anthropogenic influence was previously undetected because the current generation of climate models systematically underestimate the amplitude of forced climate variability. A new attribution technique that statistically corrects for this error suggests that observed PDO impacts—including the ongoing multidecadal drought in the western United States—can be largely attributed to human activity through externally forced changes in the PDO. These results indicate that we need to rethink the attribution and projection of multidecadal changes in regional climate.

October 27th, 1859 was a really nice early season 3.0” event in the recently released older data from Newark. It actually preceded a solid snowfall 46.9” season. Not like what happened after October 2011. Relative to the 1991-2020 climate normals, it would be a -8.7° departure October. People saw that and probably started stocking up on firewood early for the winter. There were 6 freezes by 10-30. Climatological Data for NEWARK LIBERTY INTL AP, NJ - October 1859 Click column heading to sort ascending, click again to sort descending. Sum 1643 1190 - - 429 0 2.55 3.0 Average 56.7 41.0 48.8 -8.7 - - - - Normal 66.0 49.0 57.5 - 253 21 3.79 0.2 1859-10-01 67 46 56.5 -6.8 8 0 0.29 0.0 1859-10-02 68 59 63.5 0.6 1 0 T 0.0 1859-10-03 64 47 55.5 -7.0 9 0 0.00 0.0 1859-10-04 71 48 59.5 -2.6 5 0 0.00 0.0 1859-10-05 71 52 61.5 -0.2 3 0 0.00 0.0 1859-10-06 58 50 54.0 -7.3 11 0 0.00 0.0 1859-10-07 62 42 52.0 -8.9 13 0 0.00 0.0 1859-10-08 69 51 60.0 -0.5 5 0 1.32 0.0 1859-10-09 52 46 49.0 -11.1 16 0 0.00 0.0 1859-10-10 53 41 47.0 -12.7 18 0 0.49 0.0 1859-10-11 59 37 48.0 -11.3 17 0 0.00 0.0 1859-10-12 60 45 52.5 -6.4 12 0 0.00 0.0 1859-10-13 66 46 56.0 -2.5 9 0 0.00 0.0 1859-10-14 72 55 63.5 5.4 1 0 T 0.0 1859-10-15 55 46 50.5 -7.3 14 0 0.00 0.0 1859-10-16 52 37 44.5 -12.9 20 0 0.00 0.0 1859-10-17 59 38 48.5 -8.5 16 0 T 0.0 1859-10-18 65 M M M M M 0.22 0.0 1859-10-19 M 42 M M M M 0.03 0.0 1859-10-20 45 37 41.0 -14.9 24 0 0.00 0.0 1859-10-21 41 32 36.5 -19.1 28 0 0.00 0.0 1859-10-22 44 30 37.0 -18.2 28 0 0.00 0.0 1859-10-23 51 38 44.5 -10.3 20 0 0.00 0.0 1859-10-24 52 33 42.5 -12.0 22 0 0.00 0.0 1859-10-25 59 M M M M M 0.00 0.0 1859-10-26 M 32 M M M M T T 1859-10-27 42 29 35.5 -17.9 29 0 0.20 3.0 1859-10-28 48 30 39.0 -14.1 26 0 0.00 0.0 1859-10-29 48 33 40.5 -12.3 24 0 0.00 0.0 1859-10-30 43 32 37.5 -14.9 27 0 0.00 0.0 1859-10-31 47 36 41.5 -10.6 23 0 0.00 0.0 1859-1860 46.9

The lack of rainfall and stronger ridging on today’s run allowed the 12z Euro to bring back warmer temperatures in mid-October once the cutoff exits to our SE.

The drier 12z Euro and GEM matches the recent trend of the cutoffs staying down near the Carolinas in recent months. We have been getting quite a bit of blocking to our north leading to the very heavy rainfall totals there. Plus we have been finding ways for initially wet 6-10 day forecasts to back off the closer in time we get. This high pressure to the north has been very overpowering since September 2024.

We did have a great run of early season snowfall from 2008 to 2019. The late October events in 2008 and 2011 were at the very end of the month when the climate can be more November-like when there is cold around. The November 2012 and 2019 snowstorms were very memorable.

The snowfall departures have actually been similar from DC to Boston last 7 years. I never mentioned any point of no return. Just that a warmer storm track and winter background temperatures will mean less snow than we used to get. Even in this much warmer climate we have still managed in NYC to avoid a shutout season. But places like Philly and DC have come close in recent years.

I would agree with you that we need time to see what the exact ceiling is in this much warmer climate absent an historic volcanic cooling event. My guess that I have stated is that the ceiling for NYC Central Park station is under 50”. The ceiling at Boston is probably lower than what occurred in 14-15, 95-96, and 14-15 in the 96” to 110” range. But I believe the Boston ceiling is higher than the last 7 years. So I wouldn’t be surprised if Boston beat their snowiest season out of the last 7 when they had 54.0” in 21-22.

Gee ya think. The reason we got those all-time record seasonal snowfalls from 1993 to 2015 was due to warming out of the colder and more stable era prior to those years which had less moisture to work with. So in the early stages of a warming process one of the paradoxes is that the transition years can actually be much better for snowfall than the colder and drier era that it replaced. But the warming process has progressed past the sweet spot for snowfall with the record December +13.3 and global climate shift. Still had some snowy and warm overlap years from 15-16 to 17-18. A secondary shift occurred in 18-19 leading to the dramatic changes in the Pacific and much faster Pacific Jet stream. This has caused the last 7 year record low snowfall totals. Going forward we can see several outcomes. One would be more of the same as the last 7 years with maybe a better year like 20-21 and 21-22 for snowfall at some point during the last 4 years of the 2020s. Another outcome would be a rebound off the lows and some more consistent better snowfall seasons than the last 7. But it would be very unlikely we revisit the all-time seasonal snowfall records from 1993 to 2015 absent a major volcanic eruption like we last saw in the early 1800s. Since the global climate system has significantly warmed past what was experienced during those years which allowed those outstanding snowfall outcomes.

Much stronger blocking forecast now as we approach mid-October. So a cutoff near the mid Atlantic coastline is a plausible scenario. Would like to wait until it gets under 120 hrs to get interested in a soaking rain for at least parts of the area. New run Old run

The warmer climate is directly to blame for the lowest 7 year snowfall run along the I-95 corridor from DC to Boston. It’s also the reason that this has been the warmest 10 year winter period in U.S. and Northeast history. The dramatic temperature jump since December 2015 and storm track shift since 2019 is the reason that no sites have rivaled their seasonal snowfall records set from 92-93 to 14-15. A few locations were still able to set single storm and monthly records as recently as March 18.

It was a top 3 for 100° days for many locations. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 1993 9 0 2 1949 8 0 3 2025 7 87 4 2022 6 0 - 1953 6 0 5 1988 5 0 - 1966 5 0 Time Series Summary for HARRISON, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2025 6 87 2 1999 5 4 3 2022 4 0 - 2010 4 30 - 2006 4 4 - 2005 4 9 4 2024 3 0 - 2012 3 21 - 2011 3 30 - 2001 3 7 5 2021 2 0 - 2019 2 0 - 2013 2 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2006 4 0 - 1955 4 0 2 1953 3 0 3 2025 2 87 - 2013 2 0 - 2010 2 0 - 2005 2 0 - 1999 2 0 - 1991 2 0 - 1966 2 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2010 3 0 - 1966 3 0 2 2025 2 87 - 2011 2 0 - 1993 2 0 - 1983 2 0 - 1948 2 Time Series Summary for CALDWELL ESSEX COUNTY AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2025 3 89 2 2011 2 0 - 2010 2 0 - 1999 2 151 3 2021 1 3 - 2019 1 2 - 2012 1 10 - 2005 1 1 - 2001 1 5

But we haven’t done it since the winters shifted warmer in 15-16 followed by the warmer storm track shift in 18-19. So 11 years ago and 30 years ago featured a much different winter global circulation pattern with the colder temperatures which made those outcomes possible. Pre-1994 was a colder and more stable climate era which favored snowfall outcomes focused more toward the midrange with fewer big highs and big lows for snowfall. Especially near NYC Metro, snowfall has become an all or nothing proposition since 1994 with many years well above and well below which was common prior to that era. We have seen nearly no snowfall seasons near the mid range which was common prior to 1994. So while we experienced all the record snowfall from 1994 to 2015, we didn’t pay as much attention to the very low years in the mix and lack of midrange years. We were still able to hold onto great snowfall outcomes from 2016 to 2018 around NYC with the storm tracks remaining cold. But just not quite the level of the pre 15-16 era due to the record warmth which became more common starting in December 2015 with went +13.0. Since 18-19 the continuing much warmer winters and added much warmer storm tracks have featured a dominant cutter, hugger, and suppressed Southern Stream storm tracks. This has lead to the record low I-95 snowfall since then. Most seasons have been much below with very few well above and midrange winters around NYC Metro.

Yeah, I have been pointing this out about March in recent years. The whole area near the coast has seen the lowest March decadal snowfall on record since 2020. The complete opposite of the 2010s. March Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.1 0.1 2025 0.0 0.0 2024 T T 2023 0.1 0.1 2022 0.4 0.4 2021 T T 2020 T T March Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 6.0 6.0 2019 10.4 10.4 2018 11.6 11.6 2017 9.7 9.7 2016 0.9 0.9 2015 18.6 18.6 2014 0.1 0.1 2013 7.3 7.3 2012 0.0 0.0 2011 1.0 1.0 2010 T T March Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Mean 0.5 0.5 2025 0.0 0.0 2024 0.0 0.0 2023 1.6 1.6 2022 1.6 1.6 2021 T T 2020 T T March Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Mean 8.2 8.2 2019 4.1 4.1 2018 31.9 31.9 2017 7.4 7.4 2016 3.2 3.2 2015 19.7 19.7 2014 5.4 5.4 2013 7.4 7.4 2012 T T 2011 2.1 2.1 2010 0.4 0.4

The entire I-95 corridor from DC to Boston has been in the same boat. This has been the lowest 7 year combined snowfall total for this area in recorded history. It’s a function of warmer winters and warmer storm tracks. Past instances with low 7 year snowfall totals like which ended in 1992 were more a function of drier winters and not the record warmth of the last decade. The following years with historic snowfall from 92-93 to 95-96 were during a much colder era which no longer exists. So it’s unlikely without a major volcanic eruption that we see such a strong rebound in snowfall during the reminder of the 2020s. I would be happy just to see even a smaller rebound off these record 7 year lows in at least one of the remaining 2020s winters.

Looks like a reversion to the mean. The Aleutian ridge and Southeast ridge have become our dominant winter pattern. So the model may just be defaulting to recent climatology.

It’s called xmACIS2. https://xmacis.rcc-acis.org

Yeah, the contrast between Siberia and the SSTs in the WPAC is the strongest on record for early October. It resulted in a 5 sigma jet streak out near the Aleutians recently. This has lead to the record warmth over North America from late September into early October.

That’s my point. It was easier back during the colder climate era to pull off a series of epic years like that. I agree that it was an amazing run even during that era. But the colder climate made it possible. I am sure the posters around Boston would be happy seeing a winter or two during the remainder of the 2020s bouncing back closer to the long term average in the low 40s.

Highs easily beating guidance today especially with the very dry conditions. Newark Liberty MOSUNNY 86 50 28

Yeah, areas west of the I-95 corridor are several degrees colder than NYC during the winter making it easier for them to average near or below freezing. But the rising winter temperature trend is the same at both locations. So unless this warming pattern stops, the areas just west of the I-95 corridor will also stop seeing 50”+ seasons in the coming decades.