bluewave

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.

The magnitude and the duration of the warm ups are usually more impressive than the cool downs even using the warmer climate normals.

We would need a much larger even than that once since the cooling effects only lasted into 1992 and the temperatures now are much warmer than back then. https://www.sciencedirect.com/science/article/abs/pii/S1364682624000154#:~:text=Highlights,may be worse than thought. Conclusions The cooling attributed to the Mt. Pinatubo eruption of 0.5 °C over 18 months in the literature mostly based on climate model predictions is overrated. Despite uncertainties remaining in the determination of the cooling and the duration, accounting for natural variability as described in this work by using a simple and intuitive approach reduces the cooling to up to 0.28 °C, on average 0.2 °C, and the duration is similarly reduced to 13 months. This result is consistent with other empirical

90°+ would be the warmer days during the summer. But past summers would have many days remaining in the 80s even during July. 2009 was our last cooler summer before the summers dramatically warmed since 2010. Only 1 day made it to 90° at the warm spots like Newark. Climatological Data for NEWARK LIBERTY INTL AP, NJ - July 2009 Click column heading to sort ascending, click again to sort descending. Sum 2577 2028 - - 0 293 6.60 T - Average 83.1 65.4 74.3 -3.9 - - - - 0.0 Normal 86.9 69.4 78.2 - 0 408 4.66 0.0 2009-07-01 81 66 73.5 -3.5 0 9 0.00 0.0 0 2009-07-02 79 68 73.5 -3.7 0 9 0.23 T 0 2009-07-03 81 65 73.0 -4.4 0 8 0.08 0.0 0 2009-07-04 83 65 74.0 -3.5 0 9 0.00 0.0 0 2009-07-05 81 63 72.0 -5.7 0 7 0.00 0.0 0 2009-07-06 86 60 73.0 -4.8 0 8 0.00 0.0 0 2009-07-07 82 64 73.0 -4.9 0 8 0.11 0.0 0 2009-07-08 80 59 69.5 -8.6 0 5 0.00 0.0 0 2009-07-09 74 62 68.0 -10.2 0 3 0.00 0.0 0 2009-07-10 77 58 67.5 -10.7 0 3 0.00 0.0 0 2009-07-11 79 62 70.5 -7.8 0 6 0.24 0.0 0 2009-07-12 84 64 74.0 -4.4 0 9 0.03 0.0 0 2009-07-13 83 61 72.0 -6.4 0 7 0.00 0.0 0 2009-07-14 83 60 71.5 -7.0 0 7 0.00 0.0 0 2009-07-15 87 62 74.5 -4.0 0 10 0.00 0.0 0 2009-07-16 91 71 81.0 2.5 0 16 0.00 0.0 0 2009-07-17 88 69 78.5 0.0 0 14 0.07 0.0 0 2009-07-18 86 70 78.0 -0.5 0 13 T 0.0 0 2009-07-19 85 63 74.0 -4.5 0 9 0.00 0.0 0 2009-07-20 83 67 75.0 -3.5 0 10 0.00 0.0 0 2009-07-21 73 65 69.0 -9.5 0 4 0.78 0.0 0 2009-07-22 82 65 73.5 -5.0 0 9 0.00 0.0 0 2009-07-23 79 65 72.0 -6.4 0 7 0.14 0.0 0 2009-07-24 83 65 74.0 -4.4 0 9 0.00 0.0 0 2009-07-25 84 64 74.0 -4.3 0 9 0.07 0.0 0 2009-07-26 87 69 78.0 -0.3 0 13 1.03 T 0 2009-07-27 86 69 77.5 -0.7 0 13 0.18 0.0 0 2009-07-28 87 72 79.5 1.3 0 15 T 0.0 0 2009-07-29 85 73 79.0 0.9 0 14 2.97 T 0 2009-07-30 89 73 81.0 2.9 0 16 0.00 0.0 0 2009-07-31 89 69 79.0 1.0 0 14 0.67 0.0 0

Yeah, the much warmer temperatures at places like Boston separates this record low 7 year run from previous well below average streaks. The 7 year period ending in 1992 was several degrees colder. So much of that periods lower snowfall was related to issues other than temperatures being too warm. This is why it’s unlikely that Boston will see 3 seasons before this decade is out with 83” to 107” snow. Since this much warmer climate would struggle to produce such high totals in quick succession like 1992-1993 to 1995-1996 did. This is why it will be more challenging for Boston and other l-95 cities to the south to end this current much lower snowfall period like they did back in the early to mid-90s without a major VEI 7 or larger volcanic eruption to cool the climate down temporarily. Boston average snowfall 2019-2025….26.6”……DJF average temperature….34.6° Boston average snowfall 1986-1992….29.9”……DJF average temperature….32.2° Outstanding seasons following that lower snowfall period which ended the 7 year low 1992-1993…..83.9”……31.4° 1993-1994…..96.3”……27.8° 1995-1996…..107.6”……30.9°

More summer-like than the Memorial Day weekend was. The Saturday to Monday highs were only in the upper 60s to mid 70s at the warm spots. The average high during that late May weekend is 75°. Models have 80°+ at the warm spots from Saturday through Tuesday. The average high this time of year is only 70°. Newark 2025-05-24 69 50 59.5 -6.0 5 0 0.02 0.0 0 2025-05-25 71 50 60.5 -5.3 4 0 T 0.0 0 2025-05-26 75 54 64.5 -1.6 0 0 0.00 0.0 0

2022 was the latest 80° and 2024 was the latest 82°. First/Last Summary for JFK INTERNATIONAL AIRPORT, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. 2022 05-21 (2022) 87 11-07 (2022) 80 169 2024 04-29 (2024) 82 11-01 (2024) 82 185 1950 05-07 (1950) 81 11-01 (1950) 80 177 1971 05-11 (1971) 80 10-29 (1971) 80 170 2023 04-12 (2023) 84 10-28 (2023) 81 198 1963 04-18 (1963) 82 10-21 (1963) 81 185 1949 05-05 (1949) 83 10-21 (1949) 80 168 1969 04-26 (1969) 80 10-20 (1969) 81 176 2016 05-25 (2016) 87 10-19 (2016) 86 146 1975 05-20 (1975) 81 10-15 (1975) 82 147 2021 03-26 (2021) 81 10-14 (2021) 80 201 1990 03-13 (1990) 85 10-14 (1990) 82 214 1962 04-22 (1962) 81 10-12 (1962) 81 172

It’s more like a regression to the mean for what used to be average in past decades for locations to our south. So Boston has seen a reversion last 7 seasons for what was the old average closer to NYC. Then NYC has had a 7 year average closer to what used to be the old norm from DC to Philly.

NYC needs two things in order to have a 50” snowfall season. One is an average winter temperature close to 32°or colder. The other is a cold storm track out near the benchmark. NYC has been nowhere near achieving this combination since the winters shifted so much warmer since 2015-2016. First, the winters shifted warmer in 2015-2016 which was followed by a storm track warming since 2018-2019. NYC highest snowfall total over the last decade has only been 40.9”. The coldest winter average temperature has been 34.8°.

Why do you say that? Since I am only pointing out what the current climate is capable of producing. Absent a major volcanic event, it’s statistically unlikely for NYC to see a 50” season with how much the winters and the storm tracks have warmed.