bluewave

2015-2016 was the real outlier. All the rest of the Decembers with under 1” of snow since 1950 had below average seasonal snow in NYC. This season is continuing that pattern. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Nov Dec Jan Feb Mar Apr Season 2011-2012 0.0 0.0 4.3 0.2 0.0 0.0 4.5 2006-2007 0.0 0.0 2.6 3.8 6.0 T 12.4 2023-2024 T T 2.3 3.2 M M 5.5 2022-2023 0.0 T T 2.2 0.1 0.0 2.3 2018-2019 6.4 T 1.1 2.6 10.4 0.0 20.5 2015-2016 0.0 T 27.9 4.0 0.9 T 32.8 2001-2002 0.0 T 3.5 T T T 3.5 1999-2000 0.0 T 9.5 5.2 0.4 1.2 16.3 1997-1998 T T 0.5 0.0 5.0 0.0 5.5 1996-1997 0.1 T 4.4 3.8 1.7 T 10.0 1994-1995 T T 0.2 11.6 T T 11.8 1972-1973 T T 1.8 0.8 0.2 T 2.8 1971-1972 T T 2.8 17.8 2.3 T 22.9 1965-1966 0.0 T 11.6 9.8 T 0.0 21.4 1953-1954 2.2 T 12.7 0.5 0.1 0.3 15.8

This was the first February calendar day with 6”+in Providence and under 1” in Boston since at least 2000. Maximum 1-Day Total Snowfall for Providence Area, RI (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date 1 14.7 2003-02-17 2 11.9 2017-02-09 3 10.6 2013-02-08 4 9.4 2006-02-12 5 7.9 2015-02-02 6 7.4 2013-02-09 7 7.2 2003-02-07 8 7.0 2021-02-07 9 6.2 2024-02-13 Maximum 1-Day Total Snowfall for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date 1 23.6 2003-02-17 2 17.5 2006-02-12 3 16.2 2015-02-02 4 14.8 2015-02-09 - 14.8 2013-02-09 6 13.0 2015-02-15 7 11.0 2003-02-07 8 10.9 2017-02-09 9 10.7 2014-02-05 10 10.1 2013-02-08 11 8.9 2008-02-22 12 8.5 2022-02-25 13 7.4 2015-02-08 14 6.8 2016-02-05 - 6.8 2011-02-01 16 6.5 2000-02-18 17 6.4 2016-02-08 18 5.5 2005-02-24 - 5.5 2005-02-21 20 5.3 2021-02-07 Maximum 1-Day Total Snowfall for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date 1 0.1 2024-02-13

I am guessing the rapid shifts are related to all the extra oceanic heat. So the forcing moves to areas with the warmest SSTs at any given time. Models bring the forcing back to north of Australia next few weeks accompanied by another big jet extension. So we get an early start to spring warmth near the end of February. The big -PNA trough and Southeast ridge has been our default pattern in recent years.

You can quote my whole post from above if you like. But I don’t want to get misquoted in one of our other regional forums.

It’s not about setting anyone straight. Not sure why I keep getting quoted multiple times when I am not in that thread. But I have looked at the responses and statements and have some replies. First, we have never had 9 consecutive winters this warm in the Northeast before. One of the dominant themes is that the rapid expansion of the WPAC warm pool has lead to more forcing from MJO 4-7 which had been written up in numerous studies. Forcing in this region is warm for the Northeast. So it makes perfect sense that it has been this warm in our region over the last 9 winters. I never said that we couldn’t eventually see another colder than average winter in the Northeast. Just that as long as this WPAC warm pool remains so prominent, it will probably load the dice for more warmer than colder winters over time. I am not sure what could shift this but would be open to a change if some new region of tropical forcing can emerge. The reduction in the snowfall has occurred a little later beginning with the 18-19 season. It has resulted in 5 out of the last 6 winters with below normal snowfall in NYC. It seems to be a combo of warmer than normal winters and the more hostile Pacific patterns. The epic 2010-2018 snowfall period carried over into the beginning of the warm winter period that started in December 15 with the historic +13.3 departure. My guess is that the 2010s will stand as our snowiest recent decade. When the 2020s are complete , we are on track for a significantly lower snowfall period vs the 2010s even if snowfall can improve next several seasons. But this doesn’t mean that we can’t have some great snowfall seasons in the mix like 20-21 along the way. Snowfall has been more variable while winters have been steadily warming over the years. Second, the warm blob in the NEPAC from 13-14 to 14-15 was the result of tropical forcing and not the direct cause of the pattern. This pattern quickly shifted after 2 years during the winters but became prominent in the warm season. It was a direct result of the tropical driven Rossby wave pattern. The record PAC NW heatwave a few summers ago and numerous Western drought seasons with the powerful Western Ridge were part of this pattern. An interesting question for study is why the seasonal shift occurred after the 13-14 and 14-15 winters? Feel free to quote this post if you like.

Our main issue for lack of March snowfall after the 2013 to 2019 epic run is how warm the month has become.

Rapid pattern shifts have been the norm this season which the warmer ones dominating.

While it looks like it will start out warmer than normal, it could also be a stormy pattern with a big -PNA trough out West and dueling branches of the Pacific Jet.

It’s an impressive warm signal to start March. As the El Niño begins to fade, the northern branch of the Pacific Jet becomes active again. So the ensembles have a twin Pacific jet extension of both branches. This is followed by a deep trough out West and Southeast ridge pattern taking hold to start March.

NYC has probably reached the point of needing a KU to reach normal seasonal snowfall against the 30 year averages. The much warmer temperatures makes it harder to add up a bunch of 1-3 to 2-4 or even 3-6 events like they could do before the 90s. There are just too few small to moderate events to reach normal. Since several of them turn out to be rain and we need to thread the needle for the snowier ones which are fewer in number than the old days.

5 top 10 warmest winters since that +13.3 December 2015. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2001-2002 41.6 0 2 2023-2024 41.1 16 3 2022-2023 41.0 0 - 2015-2016 41.0 0 4 2011-2012 40.5 0 5 1931-1932 40.2 0 6 1997-1998 39.6 0 7 2016-2017 39.3 0 8 2019-2020 39.2 0 9 1990-1991 39.1 0 10 1998-1999 38.6 0

Don’t know what the exact weather is going to be on March 6th, but we could be talking about 60° readings near the beginning of March. Especially if we go toward that La Niña look of deep trough out West and Southeast ridge.

You know it’s a warm winter pattern when what was supposed to be a colder week in earlier model runs struggles to stay below 40°.

I am not sure exactly how the low measurements are occurring in each given situation. But it has been an ongoing issue over the years. Notice how LGA got 3.3 with less precipitation and warmer temperatures. We know that many spots had issues with low ratios due to the warmth. Plus we lost some accumulation to the higher temperatures. The NYC ratio looks a little low to me. So maybe the snowfall there was actually in the 3.5 to 4.0 range. But this isn’t enough of a difference to materially change the flavor of the seasonal snowfall rankings since and extra 0.5 to 0.8 isn’t going to make a big difference. Past issues with low measurements https://www.nymetroweather.com/2015/12/21/central-park-conservancy-will-take-over-snowfall-measurements/ https://www.nytimes.com/2003/02/11/science/flawed-snowfall-data-jeopardize-climate-change-research.html snowfall vs precipitation today EWR…4.9…..0.58 NYC….3.2…..0.77 LGA…..3.3…..0.64 JFK……4.2…..0.65 ISP…….4.3…..0.72

At least we are doing better than BTV so far this month.

While the NYC under 2” snowfall streak has finally ended, Boston continues its under 4” run. Number of Consecutive Days Snowfall < 4 for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Run Length Ending Date 1 717 2024-02-12 2 711 2013-02-07 - 711 1987-01-18 3 702 2003-02-06 4 686 1937-12-31 5 674 1974-01-08

Thinking the measurement was probably a little late at Central Park so there was probably closer to 4” before melting and settling. Preliminary Local Storm Report National Weather Service New York NY 114 PM EST Tue Feb 13 2024 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0100 PM Snow Central Park 40.78N 73.97W 02/13/2024 M3.2 inch New York (ManhattanNY Official NWS Obs

Only recent report from Manhattan is 4” from Sam Champions rooftop garden.

Pretty scenes from Central Park.

Temperatures and rates are both important. It’s rare for NYC to get both the best rates of surrounding areas and enough cold. I believe February 2006 was one of the few times that Central Park got the best banding and was cold enough to have the heaviest accumulations from Newark east to MTP.

It only got down to 33° after it had been snowing for several hours. So not having cold air in place ahead of a storm is going to reduce accumulations to some extent especially in such an urbanized setting like NYC. Where the banding sets up is always an issue but it helps to maximize accumulations if we are colder when the storm starts.

Plus it was 40° when the precip started and the ratios weren’t the greatest so this would have been more snow if we had a cold air mass in place ahead of the storm.

Looks like Central Park getting closer to ending its under 2” streak.

Pretty winter scenes from Queens Blvd.

1.2” in Central Park so far. Central Park 1.2 in 0700 AM 02/13 Official NWS Obs