bluewave

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

The wind has had more to do with how cold it has felt the last few days. Plus the first week of January is starting colder than the last two years. But it’s warm compared to how cold January 1st-7th in 2018 and 2014 were. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending January 1-7 average temperature 2025-01-07 33.0 0 2024-01-07 36.2 0 2023-01-07 49.5 0 2022-01-07 37.6 0 2021-01-07 38.1 0 2020-01-07 41.2 0 2019-01-07 40.1 0 2018-01-07 16.4 0 2017-01-07 35.6 0 2016-01-07 32.9 0 2015-01-07 32.7 0 2014-01-07 24.0 0

New Brunswick went +4.5 last February with 16.5” of snow due to the record STJ and borderline super El Nino in mid-February allowing the Northern Stream to relax. So unless the monthly average temperature is above 40° in January and February, it’s always cold enough to snow this year. But December and March are different as +5 patterns will usually be too warm for snow. So for us storm tracks are more important than departures in January and February. Climatological Data for New Brunswick Area, NJ (ThreadEx) - February 2024 Click column heading to sort ascending, click again to sort descending. Sum 1381 820 - - 777 0 1.90 16.0 - Average 47.6 28.3 37.9 4.5 - - - - 0.9 Normal 42.8 24.0 33.4 - 885 0 2.97 9.3 2024-02-01 40 29 34.5 3.2 30 0 0.00 0.0 0 2024-02-02 48 30 39.0 7.6 26 0 0.12 0.0 0 2024-02-03 44 32 38.0 6.5 27 0 0.08 0.0 0 2024-02-04 47 27 37.0 5.4 28 0 0.00 0.0 0 2024-02-05 49 25 37.0 5.3 28 0 0.00 0.0 0 2024-02-06 48 23 35.5 3.6 29 0 0.00 0.0 0 2024-02-07 45 24 34.5 2.5 30 0 0.00 0.0 0 2024-02-08 49 26 37.5 5.4 27 0 0.00 0.0 0 2024-02-09 56 30 43.0 10.7 22 0 0.00 0.0 0 2024-02-10 60 37 48.5 16.1 16 0 0.00 0.0 0 2024-02-11 59 41 50.0 17.4 15 0 0.00 0.0 0 2024-02-12 48 33 40.5 7.7 24 0 0.00 0.0 0 2024-02-13 48 32 40.0 7.1 25 0 0.62 4.0 4 2024-02-14 43 30 36.5 3.4 28 0 0.14 1.0 2 2024-02-15 38 23 30.5 -2.8 34 0 0.00 0.0 2 2024-02-16 42 26 34.0 0.5 31 0 0.00 0.0 1 2024-02-17 44 30 37.0 3.3 28 0 0.38 11.0 11 2024-02-18 37 18 27.5 -6.4 37 0 T T 3 2024-02-19 42 24 33.0 -1.1 32 0 0.00 0.0 2 2024-02-20 43 23 33.0 -1.3 32 0 0.00 0.0 1 2024-02-21 41 20 30.5 -4.0 34 0 0.00 0.0 0 2024-02-22 43 23 33.0 -1.7 32 0 0.00 0.0 0 2024-02-23 50 29 39.5 4.5 25 0 0.14 0.0 0 2024-02-24 48 36 42.0 6.8 23 0 0.01 0.0 0 2024-02-25 45 20 32.5 -2.9 32 0 0.00 0.0 0 2024-02-26 42 25 33.5 -2.2 31 0 0.00 0.0 0 2024-02-27 56 32 44.0 8.1 21 0 0.00 0.0 0 2024-02-28 63 42 52.5 16.3 12 0 0.21 0.0 0 2024-02-29 63 30 46.5 10.2 18 0 0.20 0.0 0

At this point the definition of a good season in NYC would be going over 10” and reverting to the 2020s decadal mean around 14.2”. 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 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 2020-2021 0.0 0.0 10.5 2.1 26.0 T 0.0 38.6 2021-2022 0.0 T 0.2 15.3 2.0 0.4 0.0 17.9 2022-2023 0.0 0.0 T T 2.2 0.1 0.0 2.3 2023-2024 0.0 T T 2.3 5.2 T 0.0 7.5

The Northern Stream of the Pacific Jet has just been too overpowering. So we have continued the cutter, hugger, and suppressed Southern Stream storm tracks. If this was an El Niño with a STJ further south near the Baja then we would probably all be in double digit snowfall by now. It would have carved out more of a trough near the Tennessee Valley. Hopefully, we can get some relaxation of this theme later this month.

NYC and surrounding areas are on the lower side of La Niña seasonal snowfall by January 10th since 1980. The best La Ninas are usually frontloaded by nature. We are behind 2022 but ahead of 2012. NYC La Niña snowfall by January 10th 2025…3.7” 2023…T 2022…6.0” 2021…10.5” 2018…17.5” 2017….9.5” 2012….2.9” 2011…21.8” 2009…7.0” 2008…2.9” 2006…9.7” 2001…15.2” 1999…4.5” 1996…37.2” 1989….5.3” 1986….0.9” 1985….7.0” 1984….5.4”

Yeah, a bunch of individual lows under the block feeding into the big gyre. It may take the transient Southeast Ridge in a little over 10 days to finally weaken it. Then it looks like we get a vortex consolidating closer to Hudson Bay out toward day 15.