bluewave

That’s the point. Even in the 1970s and 1980s the NYC decadal average snowfall got close to or above 20”. The 19-20 to 23-24 new 2020s average so far in NYC is only 14.2”. So NYC will need a big increase the remainder of this season through 2029 to avoid the least snowiest decade on record. Let’s hope the BM KU storm track comes to life in a very big way. Since we don’t have a cold enough climate anymore to get near and into the 20s for seasonal snowfall with a bunch of small to moderate events like numerous years prior to the 1990s. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.6 4.4 7.1 0.1 T 14.2 2023-2024 0.0 T T 2.3 5.2 T 0.0 7.5 2022-2023 0.0 0.0 T T 2.2 0.1 0.0 2.3 2021-2022 0.0 T 0.2 15.3 2.0 0.4 0.0 17.9 2020-2021 0.0 0.0 10.5 2.1 26.0 T 0.0 38.6 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean T 0.1 2.3 7.9 5.4 3.0 1.0 19.7 1988-1989 0.0 0.0 0.3 5.0 0.3 2.5 0.0 8.1 1987-1988 0.0 1.1 2.6 13.9 1.5 T 0.0 19.1 1986-1987 0.0 T 0.6 13.6 7.0 1.9 0.0 23.1 1985-1986 0.0 T 0.9 2.2 9.9 T T 13.0 1984-1985 0.0 T 5.5 8.4 10.0 0.2 T 24.1 1983-1984 0.0 T 1.6 11.7 0.2 11.9 0.0 25.4 1982-1983 0.0 0.0 3.0 1.9 21.5 T 0.8 27.2 1981-1982 0.0 0.0 2.1 11.8 0.4 0.7 9.6 24.6 1980-1981 0.0 T 2.8 8.0 T 8.6 0.0 19.4 1979-1980 T 0.0 3.5 2.0 2.7 4.6 T 12.8 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean T 0.3 2.0 8.0 9.9 2.3 0.1 22.5 1978-1979 0.0 2.2 0.5 6.6 20.1 T T 29.4 1977-1978 0.0 0.2 0.4 20.3 23.0 6.8 T 50.7 1976-1977 0.0 T 5.1 13.0 5.8 0.6 T 24.5 1975-1976 0.0 T 2.3 5.6 5.0 4.4 T 17.3 1974-1975 0.0 0.1 0.1 2.0 10.6 0.3 T 13.1 1973-1974 0.0 0.0 2.8 7.8 9.4 3.2 0.3 23.5 1972-1973 T T T 1.8 0.8 0.2 T 2.8 1971-1972 0.0 T T 2.8 17.8 2.3 T 22.9 1970-1971 0.0 0.0 2.4 11.4 T 1.3 0.4 15.5 1969-1970 0.0 T 6.8 8.4 6.4 4.0 T 25.6

JFK is off to the slowest snowfall start of any decade going back to the 60s. The first 5 seasons of the 2020s through last year was only 15.0”. The previous slowest start was the 70s at only 15.6”. So JFK will need a big increase in KU events ASAP for through 28-29 to avoid a new lowest snowfall decade. Remember, the last 5 seasons of the 1970s averaged 25.9” to get back to 20.8” on the decade. So JFK will need a big finish to the 2020s to get above 20”. JFK seasonal snowfall 2020s so far from 19-20 to 20-24….15.0” 2010s…32.3” 2000s…25.1” 1990s…20.8” 1980s…20.4” 1970s…20.8” 1960s…30.4”

I understand that. But if you leave out the anomalous 2010s the 1950 to 2009 average was 24.6. So we can either use 25” or 26” and still see a tighter clustering around that midpoint from the 50s into early 90s on a seasonal basis.

I would say it’s been a piece of the puzzle with how warm that region has been so far this winter.

I was looking at the longer term snowfall distribution from 1951 to 2020. From the 1950s into the early 1990s we had a high number of years within 5” of that 25” average. With fewer years much higher and much lower. But starting in 1994 it’s fewer years in the median of the distribution range and more years skewed much higher or much lower. So we went from a more compressed distribution near the center to one defined more by extremes. 1951-1980…24.8” 1961-1990…23.9” 1971-2000…21.9” 1981-2010….25.3” 1991-2020…29.8” avg…25.1”

The delayed freeze-up on Hudson Bay, clouds, lower pressures, stronger winds, and warmer lakes with less ice have kept the minimum temperature departures significantly higher than the maxes this month so far in the Northeast.

I have 1” here just to the east of KHVN.

The significance is that March 2020 to 2024 was the first 5 year period with under 1” in NYC. So it has been tough to count on March for a big event this decade. Sure it’s possible we’ll eventually see some bigger Marches. But you probably want to build up a big enough snowfall surplus before March in case we see another March with well below average snow. Since relying on a big March to get near 25” is probably less likely without a snowy enough season before we get to March. The general topic of climate shifts is an interesting one. Since climate shifts usually happen without notice and only become obvious after a period of time has past. The major snowfall climate shift in NYC to ISP occurred after 1993. So we have had over 30 years of observations to confirm. NYC and ISP snowfall climatology has shifted to an all or nothing pattern over the last 30 years. Only 3 seasons in NYC have been close to the long term average of 25”. All the other seasons have experienced a larger deviation of plus or minus snowfall departures from this long term median. The previous 30 year period from the early 60s to early 90s was much colder and stable. So 12 seasons finished within about 5” inches of the 25” average. Many fewer seasons with a larger deviation above or below this average. We had a larger number of ways to get to a near average season. Since there were several seasons getting close to 25” with a bunch of smaller to moderate events. The other thing which has occurred is that a KU snowstorm has become a prerequisite for seasonal average snowfall from around NYC to ISP. In the much colder era we could get to average seasonal snowfall at times without the aid of a larger regional KU event dumping 12”+ maxes within about a 50 to 75 mile radius of NYC. 2010 to 2018 experienced the largest concentration of NESIS snowstorms in the modern climate record. So since the early 90s we have experienced fewer ways to get an average snowfall season in the 20s from NYC to ISP. And more ways to get well above or well below average snowfall. The 2020s average in NYC so far is only 14.2” through the halfway mark so far through 5 full seasons. This suggests that the only way NYC will finish this decade above 20” is for a significant increase in KU events from this winter into the following 4 remaining. If we continue with the cutter, hugger, and suppressed Southern Stream storm tracks pattern which has been in effect since December 2018, then this will be the least snowiest decade in NYC and surrounding areas history. So we need an increase in benchmark KU storm tracks as soon as possible in order to get back to average to above average snow this decade.

We want to try and get as much snow as we can before March since the 2020s Marches haven’t been as snowy as the 2010s even with the La Ninas in 21,22, and 23. 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 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

We actually got a bit of a January thaw today with 40s and lighter winds.

I agree that this looks like the Arctic shot will probably be a 5-7 day window. Then the GEFS and EPS weeklies follow the milder La Nina seasonal progression as we head into February. So hopefully we can put together some wintery events during that brief window of opportunity.

But it has underperformed relative to model forecasts. The strongest teleconnection so far had been the +PNA. But it’s possible the -EPO after the 20th will be the lowest of the winter so far. https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt 2024 12 01 -43.78 2024 12 02 -14.50 2024 12 03 -35.60 2024 12 04 -34.12 2024 12 05 -14.08 2024 12 06 28.23 2024 12 07 49.16 2024 12 08 -27.22 2024 12 09 -137.55 2024 12 10 -149.44 2024 12 11 -49.79 2024 12 12 35.08 2024 12 13 64.11 2024 12 14 70.96 2024 12 15 -21.55 2024 12 16 -72.62 2024 12 17 -59.81 2024 12 18 -48.59 2024 12 19 -98.46 2024 12 20 -88.76 2024 12 21 -9.80 2024 12 22 99.09 2024 12 23 112.77 2024 12 24 186.45 2024 12 25 280.91 2024 12 26 310.29 2024 12 27 225.40 2024 12 28 135.47 2024 12 29 75.67 2024 12 30 11.94 2024 12 31 -48.65 2025 01 01 -42.88 2025 01 02 -66.19 2025 01 03 -18.87 2025 01 04 83.75 2025 01 05 65.62 2025 01 06 -11.42 2025 01 07 0.43

That January 20th to 27th period could be very important for the whole winter. The magnitude of the cold may determine if we see our first colder winter here in 10 years. Since La Niña Februaries usually have the highest winter temperature departure for us. We need a big enough cold departure to stay in tact against any February warm ups. Hopefully, NYC can break its 4” losing streak before the pattern modifies as we approach February.

We should get our January thaw next weekend followed by what could be the coldest temperatures this month and possibly winter so far. This is looking like the first legit Arctic airmass to enter North America this winter. Details will depend in the short term -EPO intensity.

The Euro and EPS have been running too cold at times like today. Remember it had highs staying under 32° today. Several spots made it into the mid to upper 30s.

January 2022 was pretty impressive on the back bays but nothing like February 2015 on our local waterways. https://tomsriver.shorebeat.com/2022/02/fire-and-ice-blazing-sunset-blankets-a-frozen-barnegat-bay-video-gallery/

The snow cover is helping plus the airmass isn’t crossing the warmer Lakes and the delayed freeze-up on Hudson Bay which is keeping the Northeast warmer.

The 07-08 La Niña developed during the summer of 07 after a much weaker El Niño and lingered into 08-09. https://www.climate.gov/news-features/blogs/enso/january-2025-update-la-nina-here Why was La Niña so slow to develop? The short answer to this is “we don’t yet know.” The emergence of La Niña-like atmospheric conditions before substantial tropical Pacific Ocean surface cooling was unusual, though. The global oceans have been running much, much warmer than average for more than a year, which might have had a hand in La Niña’s delay. When we calculate the Niño-3.4 index but account for the temperature of the tropical oceans (the “Relative Niño-3.4 index”) we get an index that’s been in La Niña territory for months. Only this past year or so has the difference between the traditional and relative Niño-3.4 indexes been so large, and we’re still researching this new measurement and all the implications for ENSO development and impacts in a warmer world.

The delayed start from such a warm global background state and continued 1+2 warming makes this one of the more unusual La Niña events that we have seen. The equatorial Eastern Pacific off the South American coast has warmed in recent weeks *. The rains are felt in the entrance basins to #Poechos and #SanLorenzo where the 30% storage of the useful volume estimated by the operators has already been exceeded. It's raining again today, which will translate into higher income. *This does not mean that we are heading towards a #NiñoCostero just in case. But it helps tremendously to improve the contribution of humidity that is used, among other processes, for the formation of rain.

Yeah, the minimum departure is currently running +8.4 up in Caribou through the 8th. My guess is it’s a function of how warm Canada has been around Hudson Bay with the delayed freeze-up. Plus the lower pressures, very strong winds, and clouds limiting the overnight low potential. Climatological Data for Caribou Area, ME (ThreadEx) - January 2025 Click column heading to sort ascending, click again to sort descending. Sum 187 107 - - 371 0 1.03 8.0 - Average 23.4 13.4 18.4 4.8 - - - - 2.4 Normal 22.2 5.0 13.6 - 412 0 0.80 6.6 2025-01-01 39 31 35.0 20.5 30 0 0.47 0.2 0 2025-01-02 34 24 29.0 14.8 36 0 0.19 2.2 1 2025-01-03 24 13 18.5 4.6 46 0 0.07 1.5 3 2025-01-04 13 3 8.0 -5.7 57 0 0.01 0.2 3 2025-01-05 10 -3 3.5 -9.9 61 0 T T 3 2025-01-06 18 7 12.5 -0.7 52 0 T T 3 2025-01-07 25 15 20.0 7.1 45 0 0.06 0.8 3 2025-01-08 24 17 20.5 7.8 44 0 0.23 3.1 3 2025-01-09 M M M M M M M M M 2025-01-10 M M M M M M M M M 2025-01-11 M M M M M M M M M 2025-01-12 M M M M M M M M M 2025-01-13 M M M M M M M M M 2025-01-14 M M M M M M M M M 2025-01-15 M M M M M M M M M 2025-01-16 M M M M M M M M M 2025-01-17 M M M M M M M M M 2025-01-18 M M M M M M M M M 2025-01-19 M M M M M M M M M 2025-01-20 M M M M M M M M M 2025-01-21 M M M M M M M M M 2025-01-22 M M M M M M M M M 2025-01-23 M M M M M M M M M 2025-01-24 M M M M M M M M M 2025-01-25 M M M M M M M M M 2025-01-26 M M M M M M M M M 2025-01-27 M M M M M M M M M 2025-01-28 M M M M M M M M M 2025-01-29 M M M M M M M M M 2025-01-30 M M M M M M M M M 2025-01-31 M M M M M M M M M

The cold departures so far in January are being driven by the cooler maxes rather than the minimums. The strong winds blowing across the warm lakes along with the clouds are keeping the minimum temperatures up. This is why even interior spots around our area have been struggling to get into the single digits like they often do during colder patterns in early January. Time Series Summary for SUSSEX AIRPORT, NJ Click column heading to sort ascending, click again to sort descending January 1-8 minimum temperature 2025-01-08 17 1 2024-01-08 18 0 2023-01-08 25 0 2022-01-08 12 0 2021-01-08 17 0 2020-01-08 22 0 2019-01-08 20 0 2018-01-08 -4 2 2017-01-08 13 0 2016-01-08 4 0 2015-01-08 2 0 2014-01-08 -9 0 2013-01-08 8 0 2012-01-08 9 0 2011-01-08 0 0

I am hoping NYC can find a way to sneak in a 4”+ event during the PNA transition being forecast for later January. Maybe some type of overrunning once the Southeast Ridge starts flexing? But no guarantees with the way things have been going. Would want to see something within 120 hrs on all 3 models to be believable. Jan 20-27 Jan 27 to Feb 3

Yeah, the mismatch analogs I listed were December based. But I was uncertain how the actual process would turn out since this La Niña was so much weaker than the past mismatch instances. So the Northern Stream of the Pacific Jet was much stronger than the past mismatch Decembers leading to the cutter, hugger, and suppressed Southern Stream storm tracks. This has been the theme since the 2018-2019 winter which has continued into early January so far. It could be the same warm background SST state in the Pacific which slowed the La Niña SST response also being related somehow to the faster Northern Stream than past mismatch La Niña patterns.

The delayed freeze-up on Hudson Bay and warmer lakes really moderating the cold. https://sites.google.com/view/arctic-sea-ice/home/nsidc-arctic

Yeah, the 7 station average for January so far would be a little above average in 81-10 normals. We are currently running -0.6 in 91-20 averages. The warmth in Canada has worked down into the Northeast as Caribou is +4.8 so far. Same pattern as recent years with the coldest departures going to our west and south. EWR….-0.6 NYC….-2.4 JFK…..+0.5 LGA…..-2.2 HPN….+1.0 BDR….-0.4 ISP……-0.1