bluewave

But you knew it wouldn’t take long for the inevitable sun angle posts.

Almost reminds me of October 2011 when NYC had the early month near record 84° warmth followed by the all-time biggest October snowstorm later in the month. 10/9 86 in 1916 84 in 2011 84 in 1990+ Climatological Data for NY CITY CENTRAL PARK, NY - October 2011 Click column heading to sort ascending, click again to sort descending. Sum 1977 1563 - - 255 17 6.09 2.9 - Average 63.8 50.4 57.1 -0.8 - - - - 0.0 Normal 64.5 51.4 57.9 - 240 22 4.38 0.1 2011-10-01 67 50 58.5 -5.0 6 0 0.39 0.0 0 2011-10-02 64 50 57.0 -6.1 8 0 0.06 0.0 0 2011-10-03 58 48 53.0 -9.7 12 0 0.05 0.0 0 2011-10-04 63 49 56.0 -6.3 9 0 0.00 0.0 0 2011-10-05 71 53 62.0 0.1 3 0 0.00 0.0 0 2011-10-06 67 47 57.0 -4.5 8 0 0.00 0.0 0 2011-10-07 66 48 57.0 -4.1 8 0 0.00 0.0 0 2011-10-08 77 54 65.5 4.7 0 1 0.00 0.0 0 2011-10-09 84 60 72.0 11.6 0 7 0.00 0.0 0 2011-10-10 81 61 71.0 11.0 0 6 0.00 0.0 0 2011-10-11 73 62 67.5 7.9 0 3 0.00 0.0 0 2011-10-12 63 58 60.5 1.2 4 0 0.45 0.0 0 2011-10-13 66 58 62.0 3.1 3 0 0.34 0.0 0 2011-10-14 70 57 63.5 5.0 1 0 1.02 0.0 0 2011-10-15 65 54 59.5 1.3 5 0 0.00 0.0 0 2011-10-16 66 54 60.0 2.2 5 0 0.00 0.0 0 2011-10-17 65 57 61.0 3.5 4 0 T 0.0 0 2011-10-18 68 54 61.0 3.9 4 0 0.01 0.0 0 2011-10-19 62 60 61.0 4.2 4 0 1.12 0.0 0 2011-10-20 67 54 60.5 4.1 4 0 0.01 0.0 0 2011-10-21 56 50 53.0 -3.1 12 0 0.00 0.0 0 2011-10-22 60 47 53.5 -2.3 11 0 0.00 0.0 0 2011-10-23 59 50 54.5 -0.9 10 0 0.00 0.0 0 2011-10-24 61 50 55.5 0.4 9 0 0.00 0.0 0 2011-10-25 62 50 56.0 1.2 9 0 0.00 0.0 0 2011-10-26 62 51 56.5 2.1 8 0 0.00 0.0 0 2011-10-27 61 38 49.5 -4.6 15 0 0.63 0.0 0 2011-10-28 49 36 42.5 -11.3 22 0 0.00 0.0 0 2011-10-29 45 33 39.0 -14.5 26 0 2.00 2.9 0 2011-10-30 46 33 39.5 -13.7 25 0 0.01 T 0 2011-10-31 53 37 45.0 -7.8 20 0 0.00 0.0 0

Really rare storm track with just enough cold in place along the Gulf Coast. The pattern leading up to the event wasn’t that cold in the area.There was an 81° record high a few weeks ago. It has been much warmer than the February 1895 was ahead of the previous record snow. Also notice how warm the nearby Gulf has been. 1/5 81 in 2025 79 in 2005 77 in 1955 Climatological Data for Baton Rouge Area, LA (ThreadEx) - January 2025 Click column heading to sort ascending, click again to sort descending. Sum 1183 758 - - 328 3 1.94 0.0 Average 59.2 37.9 48.5 -3.2 - - - - Normal 61.9 41.4 51.7 - 275 9 4.22 2025-01-01 64 42 53.0 1.0 12 0 0.00 0.0 2025-01-02 65 39 52.0 0.1 13 0 0.00 0.0 2025-01-03 70 48 59.0 7.2 6 0 0.00 0.0 2025-01-04 65 45 55.0 3.2 10 0 T M 2025-01-05 81 52 66.5 14.8 0 2 0.40 0.0 2025-01-06 52 33 42.5 -9.2 22 0 0.00 0.0 2025-01-07 49 30 39.5 -12.1 25 0 0.00 0.0 2025-01-08 48 30 39.0 -12.6 26 0 0.00 0.0 2025-01-09 46 31 38.5 -13.1 26 0 0.04 M 2025-01-10 50 40 45.0 -6.6 20 0 1.15 M 2025-01-11 51 33 42.0 -9.5 23 0 0.00 0.0 2025-01-12 51 31 41.0 -10.5 24 0 0.35 M 2025-01-13 65 42 53.5 1.9 11 0 0.00 0.0 2025-01-14 59 34 46.5 -5.1 18 0 0.00 0.0 2025-01-15 62 48 55.0 3.4 10 0 T 0.0 2025-01-16 67 37 52.0 0.4 13 0 0.00 0.0 2025-01-17 64 35 49.5 -2.2 15 0 T M 2025-01-18 78 53 65.5 13.8 0 1 T 0.0 2025-01-19 53 31 42.0 -9.8 23 0 0.00 0.0 2025-01-20 43 24 33.5 -18.3 31 0 0.00 0.0 2025-01-21 M M M M M M M M 2025-01-22 M M M M M M M M 2025-01-23 M M M M M M M M 2025-01-24 M M M M M M M M 2025-01-25 M M M M M M M M 2025-01-26 M M M M M M M M 2025-01-27 M M M M M M M M 2025-01-28 M M M M M M M M 2025-01-29 M M M M M M M M 2025-01-30 M M M M M M M M 2025-01-31 M M M M M M M M Climatological Data for Baton Rouge Area, LA (ThreadEx) - February 1895 Click column heading to sort ascending, click again to sort descending. Sum 1285 797 - - 493 0 5.79 12.5 Average 53.5 33.2 43.4 -12.5 - - - - Normal 66.6 45.3 55.9 - 279 25 4.42 1895-02-01 58 41 49.5 -3.7 15 0 0.70 0.0 1895-02-02 48 38 43.0 -10.4 22 0 0.02 0.0 1895-02-03 54 37 45.5 -8.1 19 0 T 0.0 1895-02-04 56 36 46.0 -7.8 19 0 0.00 0.0 1895-02-05 56 36 46.0 -7.9 19 0 0.03 0.0 1895-02-06 70 M M M M M T 0.0 1895-02-07 M 17 M M M M 0.00 0.0 1895-02-08 36 11 23.5 -31.0 41 0 0.00 0.0 1895-02-09 37 20 28.5 -26.2 36 0 0.00 0.0 1895-02-10 40 34 37.0 -17.9 28 0 0.56 0.0 1895-02-11 54 33 43.5 -11.6 21 0 2.15 0.0 1895-02-12 38 30 34.0 -21.4 31 0 0.00 0.0 1895-02-13 39 25 32.0 -23.6 33 0 0.00 0.0 1895-02-14 34 34 34.0 -21.8 31 0 0.60 6.0 1895-02-15 33 24 28.5 -27.5 36 0 0.65 6.5 1895-02-16 37 26 31.5 -24.7 33 0 T T 1895-02-17 47 20 33.5 -22.9 31 0 0.00 0.0 1895-02-18 62 28 45.0 -11.7 20 0 0.00 0.0 1895-02-19 55 36 45.5 -11.4 19 0 T 0.0 1895-02-20 60 28 44.0 -13.1 21 0 0.00 0.0 1895-02-21 M M M M M M 0.00 0.0 1895-02-22 M M M M M M 0.00 0.0 1895-02-23 M M M M M M 1.08 0.0 1895-02-24 73 47 60.0 2.0 5 0 0.00 0.0 1895-02-25 73 49 61.0 2.8 4 0 0.00 0.0 1895-02-26 72 50 61.0 2.6 4 0 0.00 0.0 1895-02-27 77 49 63.0 4.4 2 0 0.00 0.0 1895-02-28 76 48 62.0 3.1 3 0 0.00 0.0

It’s been an interesting progression. The dry pattern in NJ actually started last June while places to the east were still wet from the record rains since July 23. Then everyone got dry from August 21st to November 21st. Spots from LI into CT were very wet with 10”+ rainfall totals through New Year’s Eve. January has been dry across the area as it’s tough to get much precipitation here with the Southeast Ridge suppressed. My guess is that February will be wetter than January was as the Southeast Ridge flexes like it usually does with La Niña Februaries. But if the storm track shifts back too far toward the Great Lakes, then the wettest relative to the means may go to our west. If that’s the case, then we’ll really need a wet spring in order to avoid this drought carrying over into next summer.

I believe this was the coldest at Walpack since January 2018 when the got down to -16°. https://www.njweather.org/data Walpack NJ 2025-01-21 Mesonet 15 -15 Walpack NJ 2018-01-01 Mesonet 19 -16

We actually had one of our coldest Februaries that month around 24° in NYC. So the record cold is much less extensive this time around with the core going to our south and west again. More narrowly focused Arctic outbreaks covering smaller geographic regions has become the new normal. Just like we were much colder during past instances then when Texas got record cold compared to February 2021. Climatological Data for NY CITY CENTRAL PARK, NY - February 1895 Click column heading to sort ascending, click again to sort descending. Sum 865 495 - - 1132 0 0.46 9.0 Average 30.9 17.7 24.3 -11.6 - - - - Normal 42.2 29.5 35.9 - 816 0 3.19 1895-02-01 39 21 30.0 -3.7 35 0 0.00 0.0 1895-02-02 31 16 23.5 -10.3 41 0 0.16 4.0 1895-02-03 31 12 21.5 -12.4 43 0 0.00 0.0 1895-02-04 30 11 20.5 -13.5 44 0 0.00 0.0 1895-02-05 11 0 5.5 -28.7 59 0 0.00 0.0 1895-02-06 10 -4 3.0 -31.3 62 0 0.00 0.0 1895-02-07 13 6 9.5 -24.9 55 0 0.17 S 1895-02-08 8 2 5.0 -29.6 60 0 0.13 5.0A 1895-02-09 19 4 11.5 -23.3 53 0 0.00 0.0 1895-02-10 24 18 21.0 -13.9 44 0 0.00 0.0 1895-02-11 30 17 23.5 -11.6 41 0 0.00 0.0 1895-02-12 34 18 26.0 -9.3 39 0 0.00 0.0 1895-02-13 27 21 24.0 -11.4 41 0 T T 1895-02-14 31 21 26.0 -9.6 39 0 0.00 0.0 1895-02-15 35 22 28.5 -7.3 36 0 0.00 0.0 1895-02-16 33 21 27.0 -9.0 38 0 0.00 0.0 1895-02-17 40 26 33.0 -3.2 32 0 0.00 0.0 1895-02-18 42 26 34.0 -2.4 31 0 0.00 0.0 1895-02-19 43 30 36.5 -0.1 28 0 0.00 0.0 1895-02-20 34 25 29.5 -7.3 35 0 0.00 0.0 1895-02-21 43 30 36.5 -0.5 28 0 0.00 0.0 1895-02-22 33 18 25.5 -11.7 39 0 T T 1895-02-23 29 16 22.5 -14.9 42 0 0.00 0.0 1895-02-24 30 15 22.5 -15.1 42 0 0.00 0.0 1895-02-25 41 26 33.5 -4.4 31 0 0.00 0.0 1895-02-26 34 19 26.5 -11.6 38 0 0.00 0.0 1895-02-27 44 20 32.0 -6.3 33 0 0.00 0.0 1895-02-28 46 38 42.0 3.5 23 0 0.00 0.0

https://berkeleyearth.org/global-temperature-report-for-2024/ However, the warming spike in 2023/2024 appears to have deviated significantly from the previous trend. If we were to assume that global warming was continuing at the same rate as during the 50-year period 1970-2019, then the 2023/2024 excursion would be by far the largest deviation from that trend, with only a roughly 1-in-100 chance of occurring solely due to natural variability. While 1-in-100 chance events do sometimes occur, we consider it more likely that the recent rate of global warming has been larger than expected, exceeding both the previous trend and what would be expected when considering only the observed pattern of greenhouse gas emissions.

Yeah, it’s the same theme this month that we saw with the record cold going to our south and west back in February 2021. Notice the warmer departures in Maine also. Very difficult for cold to be focused over the Northeast these days. The last time the core of a record cold airmass was focused over the Northeast for a month was way back in February 2015.

The Southeast Ridge should be a bigger player in February than January so we should lose the suppression pattern of this month.

The sensible weather here since October hasn’t been matching up with the MJO expectations for the past similar phases and corresponding 500mb patterns.

To me any low below 32° in the winter is cold since you need a jacket and sweatshirt. But I was referencing the earlier Euro forecasts which were too cold by nearly 10°. Like the EPS forecast you mentioned of the high not getting above 32° in NYC from the 6th to 16th. Lows in the 10-12° range in January for NYC aren’t considered that anomalous compared to what we used to get in the past. What is unusual is the snowfall so far this month in NYC. We are on track for the lowest January snowfall for a NYC monthly average temperature of around 30.0° and colder. I know people keep saying cold and dry like the 70s and 80s. But NYC usually got much better snows even back then when January would have average monthly temperatures near this temperature range. 2025…31.8°…..3.0”….so far 2022…30.3°….15.3” 2018….31.7°….11.2” 2015…29.9°….16.9” 2014…28.6°….19.7” 2011….29.7°….36.0” 2009..29.7°….9.0” 1996..30.5°…26.1” 1994…25.5°..12.0” 1988….29.5°…13.9” 1985….28.8°….8.4” 1984…29.9°….11.7” 1982…26.1°…..11.8” 1981…26.2°….8.0” 1978…28.0°….20.3” 1977….22.0°….13.0” 1976….27.3°….5.6” 1971…..26.9°….11.4”

That’s a very good question. All we know is that NYC frequently got to the middle 19” to 29” snowfall range with or without KU snowstorms in the 1970s and 1980s. So in the much colder climate a KU wasn’t a prerequisite to get near to over 20” like it has become since the 1990s. 87-88….19.1”….No KU 86-87…..23.1”…KU 84-85….24.1”…No KU 83-84….25.4”…No KU 82-83….27.2”….KU 81-82….24.6”…KU 78-79….29.4”….KU 76-77….24.5”….No KU 73-74…..23.5”…No KU 71-72…..22.9…..No KU

That was due to the great radiational cooling and snow cover closer to your area. Since many spots from NYC to the immediate shoreline need the winds to stay up for their coldest readings when the flow is N to NW down the Hudson Valley and not the W. The Euro originally was too suppressed and didn’t have the heavier snows near your area. It also was initially too cold for the coast and missed the rain and 40° warmth before the changeover on Sunday. Which combined with the subsidence and weaker precip rates for lower totals near the coast.

As expected the Euro was nearly 10° too cold in spots around NYC and the coast with the westerly flow crossing the warm Great Lakes region. Current low so far of 12° in NYC. So NYC and coastal sections wont be as cold as we were in early February 2023 on the N to NW flow when NYC got to 3° with subzero lows across the CT Shoreline.

My guess is that the variables have increased since 18-19 due to these expanding record marine heatwaves in basins like the Pacific. So the Northern stream of the Pacific Jet wasn’t able to relax this winter to date compared other La Ninas with +PNAs and -AOs. Plus the magnitude and location actual 500 mb anomalies has shifted relative to past +PNA and -AO La Nina episodes. So patterns in the recent 30 year past that were favorable for heavy snows and become less so recently. Something similar happened with the near record -AO during December 2022. Past La Ninas in this range produced record snowstorms like in the Boxing Day blizzard in 2010. But we got through that pattern with very little snowfall to show for it. So changing jet dynamics and storm tracks have added a new layer to our understanding of what 500mb longwave patterns will produce for us now. We have to do the best we can with the data that is available. Since climate shifts are usually are rear view mirror assessments that we only notice once we are already into a new regime. It’s uncertain how much longer this faster Pacific Jet pattern will continue with cutters, huggers, and suppressed southern stream storm tracks.

I would rather have a warmer winter like 15-16 through this point with a widespread 20-30” snowstorm than the seasonable temperatures and the struggle for more than a few inches of snow at a time of this winter so far.

This year is definitely going against past La Ninas with a +PNA December into January with -AO intervals since the 1990s. It’s the lowest snowfall across the coastal areas for any of those years through January 19th. So the lack of BM KU storms so far this winter is something new with La Ninas with +PNAs and -AO intervals since the 90s. All the other years had a Northern Stream of the Pacific Jet which was much weaker than this year so far allowing better snowfall. +PNA La Niña Decembers into January at times with -AOs intervals snowfall through January 19th 2025….NYC….5.8”…..ISP….4.8” 2021….NYC…..10.5”….ISP….7.5” 2018….NYC….17.9”…..ISP….22.0” 2006…NYC…..11.7”….ISP….12.8” 2001….NYC…..15.2”…ISP….16.0” 1996….NYC…..36.9”…ISP..44.4”

It seems like something changed with Euro and EPS after one of the updates in 2014 and 2015. The Euro and EPS were spot on from 7-8 days out with Hurricane Sandy in 2012. It was the first model to jump on Nemo in February 2013 around 5 days out. Then the high profile storm track error with the blizzard in January 2015 when it was too far NW. This was followed by the January 2016 blizzard forecast from a day out which had the heaviest snowfall axis to our south instead of across the NYC Metro which verified. So it was too suppressed. More often than not in recent years the longer range bias with tracks near the coast has been suppression. It would be great if we could generate a track error database for every East Coast low from each of the models like is done by the NHC with tropical cyclone model track errors. Since the headline model skill scores we see on the various sites don’t specifically have an East Coast storm system statistics. Even in the older era back in the 90s, I believe the Euro was first to have a closer to correct idea with March 1993 and January 1996. While all the models missed the early rapid deepening in the Gulf in March 93, I believe the Euro was closer on the track than the old AVN MRF. it also had January 96 more defined and further north than the AVN MRF which was too suppressed. So I am not sure what happened to the Euro and EPS as the animation below from February 2021 seems to have become the norm for that model at times in recent years.

3 mid range 20s years from 69-70 to 73-74 with none since 19-20.

The sample size of the shift in snowfall distribution in NYC is 60 years long. NYC had 18 seasons with a mid range snowfall from 19” to 30” from 63-64 to 92-93. From 93-94 to 23-24 NYC only had only 4 of these mid range seasons. Nearly all of the seasons since the 90s have been dominated by well above and well below normal snowfall. The last 6 years matches this pattern which was established in 93-94 with only one season in the 19-30” range which was common back in the 63-64 era. My guess on why this is happening is that it’s probably a function of the warming the climate has experienced. From 63-64 to 92-93 we were in much more of a stable climate with significantly colder winters. Our storms were a mix of larger KUs over 10” and 12”,moderate 3-6 or 4-8” type events, and small 1-3” to 2-4” type events. So more balanced snowfall seasons toward a mid range and fewer very high and very low extremes. Since 93-94 our snowfall has become dominated by seasons with numerous KUs where someone around NYC Metro would regularly get a 10” or 12” event from near EWR out to Eastern LI. The seasons when these KUs didn’t appear were mostly below to well below average. Over this period we have experienced the greatest winter warming in modern times. 09-10 to 17-18 represented the greatest era for NESIS KU snowstorms. So it’s no coincidence 15-16 was the first winter with a new heaviest snowstorm on record in NYC and a +13 temperature month along with a subzero low. So volatility has increased along with this warming. The big question going forward is if this most recent shift since 18-19 to cutter, hugger, and suppressed southern stream storm tracks will continue. On that point I agree with you that a 6 year period is too small a sample size to make any conclusions about storm tracks in the future. It’s possible that benchmark KU tracks could make a return. But expecting a 09-10 to 17-18 sustained high rate of KUs may be a challenge. So I stand by my observation from the long term data that a return to KU benchmark snowstorm tracks will be a prerequisite for NYC and other coastal areas to get the snowfall average back above 20” for the 2020s and the future decades. Since we don’t have the more cold and stable climate when we could rely on small to moderate events only at times to get something closer to a long term midrange somewhere in the 20s for snowfall.

The current climate is much warmer than 1970-1999. So coastal areas near NYC can’t get over 20” on the season anymore without a KU. We had numerous seasons during that era around NYC Metro without a KU and 20”+ snowfall. Since there were numerous smaller to moderate events when the temperatures were less marginal for snow. Since the 1990s we have been depending on much larger snowstorms for our seasonal snowfall. So the epic 2010-2018 KU snowfall era was masking the warming pattern. If we can’t get back to more regular KU tracks like we had from 2010 to 2018, then the new seasonal snowfall from EWR out to ISP will be under 20” like it has been in the 2020s so far.

Yeah, these cuttter, hugger, and suppressed southern stream storm tracks have really dominated since 18-19. Leaves very little room for a big KU to rapidly deepen out near the benchmark. The one exception was 20-21 for NYC into NJ and 22 which favored points east of NYC. That’s why I continue to stand by my observation that for NYC to get to 25” or greater on any season they will need to see the BM KU storm track return. Since we aren’t cold enough to get to average with a collection of small to moderate events like was the case during several years in the 1970s and 1980s. It was amazing how many historic BM KUs we had from 09-10 to 17-18.

Nice little event here on the CT Shoreline with 2” just east of HVN.