bluewave

While March 1993 was a unique case, it matches the general theme since the 1990s. The December to March storm tracks have shifted east over toward the warm pool. The main winter storm tracks since 2010 have been benchmark like Jan 16 or coastal hugger like Dec 2020. The NJ inland runner track hasn’t been as common. In fact, State College hasn’t had a 16”+ snowstorm since since Feb 2003.

Winter 50° days in NYC have become more common than highs that don’t get above freezing.

Yeah, their snowfall has been cut nearly in half since the early 1990s. The big lows that used to track right over NJ and dump heavy snow in Central PA have pretty much become non-existent these days. It could be related to the record warm pool favoring BM tracks instead of more like March 1993.

Things get more interesting if we take a longer look at winter temperatures and seasonal snowfall at Islip since the early 1960s. There is decrease in snow cover days and an increase in total seasonal snowfall. Sharper warming trend with nearly double the number of winter 50° days. So quick warm ups after snowstorms have resulted in quick snowmelts after the storms.

That’s a good question. While Islip snowfall has doubled since 1981, the number of days with 1” of snowfall on the ground has only increased by a few days. So it’s one of the features of our warming climate. All these 50° and 60° days around our snowstorms hasn’t allowed a big jump in snow cover days for going from near 20” to 40” since 1981. So we get quick snowmelts.

December 11-20 has been the snowiest part of the month in NYC since 2011. So it’s possible NYC could pick up its first snow of the season with this storm. Need a much stronger 500 mb low like the CMC to pick up more than a T-2”. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Dec 1 to Dec 10 Missing Count 2021-12-10 T 0 2020-12-10 T 0 2019-12-10 1.6 0 2018-12-10 0.0 0 2017-12-10 4.6 0 2016-12-10 0.0 0 2015-12-10 0.0 0 2014-12-10 1.0 0 2013-12-10 2.1 0 2012-12-10 0.0 0 2011-12-10 0.0 0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Dec 11 to Dec 20 Missing Count 2021-12-20 0.0 0 2020-12-20 10.5 0 2019-12-20 0.9 0 2018-12-20 T 0 2017-12-20 2.4 0 2016-12-20 3.2 0 2015-12-20 0.0 0 2014-12-20 T 0 2013-12-20 6.5 0 2012-12-20 0.0 0 2011-12-20 0.0 0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Dec 21 to Dec 31 Missing Count 2021-12-31 0.2 0 2020-12-31 0.0 0 2019-12-31 T 0 2018-12-31 T 0 2017-12-31 0.7 0 2016-12-31 T 0 2015-12-31 T 0 2014-12-31 T 0 2013-12-31 T 0 2012-12-31 0.4 0 2011-12-31 0.0 0

The last time we had a top 10 coldest winter was 1976-1977. The last top 20 was 93-94. 14-15 would be the coldest of the last decade coming in at 22nd place. But while February had impressive sustained cold, the lowest temperatures never really came close to the 76-94 era around the region. It’s funny that NYC couldn’t go below 0°in February 2015, but did it in the record warm winter on Valentines Day 2016. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 1917-1918 25.7 0 2 1880-1881 26.5 0 3 1903-1904 27.3 0 4 1919-1920 27.4 0 5 1874-1875 27.7 4 - 1872-1873 27.7 0 6 1904-1905 28.1 0 7 1935-1936 28.3 0 8 1976-1977 28.4 0 - 1884-1885 28.4 0 - 1882-1883 28.4 0 9 1892-1893 28.6 0 - 1887-1888 28.6 0 10 1878-1879 29.0 2 11 1933-1934 29.1 0 12 1871-1872 29.5 2 13 1962-1963 29.9 0 - 1922-1923 29.9 0 - 1885-1886 29.9 0 - 1876-1877 29.9 0 14 1947-1948 30.0 0 - 1886-1887 30.0 0 - 1883-1884 30.0 0 15 1894-1895 30.2 0 16 1977-1978 30.3 0 17 1969-1970 30.5 0 - 1944-1945 30.5 0 18 1911-1912 30.7 0 19 1958-1959 30.8 0 20 1993-1994 31.1 0 - 1934-1935 31.1 0 21 2002-2003 31.2 0 - 1967-1968 31.2 0 - 1909-1910 31.2 0 - 1870-1871 31.2 4 22 2014-2015 31.4 0 - 1921-1922 31.4 0

It would be nice if some long range forecasting blogs update their climo and stop discussing winter analog packages from the colder 76-77 to 93-94 era. It’s been difficult to find many winter analogs even before the 15-16 super El Niño that are still valid. But discussing analogs from colder eras seems to bring a sense of nostalgia so I can understand where it is coming from. But the likelihood of seeing a repeat of January 1977, 1982, 1985, or 1994 is pretty much nonexistent in our much warmer world.

If we define winter as the number of days with the average temperature under 40°, then EWR to POU have lost about 3 weeks since 1950.

Yeah, the GFS skill dropped with the upgrade.

There were 29 seasons with over 35” and under 15.0” at Islip in roughly the last 30 years. Only 8 seasons with such extreme highs or lows during the previous roughly 30 interval. So it’s has been an all or nothing snowfall pattern at ISP since the early 1990s. Over 35” and under 15” years bolded Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season 2021-2022 0.0 T 0.3 31.8 3.3 1.6 0.0 37.0 2020-2021 T 0.0 7.5 1.1 24.9 T T 33.5 2019-2020 0.0 0.1 4.2 2.5 0.0 T T 6.8 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 12.8 2017-2018 0.0 T 6.0 22.0 1.4 31.9 4.6 65.9 2016-2017 T T 3.2 14.0 14.7 7.4 T 39.3 2015-2016 0.0 0.0 T 24.8 13.2 3.2 0.2 41.4 2014-2015 0.0 T 0.4 30.2 13.4 19.7 0.0 63.7 2013-2014 0.0 0.3 8.1 25.2 24.5 5.4 0.2 63.7 2012-2013 0.0 4.2 0.6 3.3 31.4 7.4 0.0 46.9 2011-2012 0.3 0.0 T 3.8 0.6 T 0.0 4.7 2010-2011 0.0 T 14.9 34.4 3.9 2.1 T 55.3 2009-2010 0.0 0.0 25.3 6.4 21.7 0.4 0.0 53.8 2008-2009 0.0 T 10.4 8.9 3.3 13.6 T 36.2 2007-2008 0.0 0.0 2.6 0.8 7.3 T 0.0 10.7 2006-2007 0.0 T 0.0 1.0 4.2 3.8 T 9.0 2005-2006 0.0 0.5 7.6 4.7 19.9 3.2 0.1 36.0 2004-2005 0.0 T 7.0 21.5 17.0 13.3 0.0 58.8 2003-2004 0.0 0.0 15.5 19.1 1.1 5.7 0.0 41.4 2002-2003 0.0 1.0 16.0 2.6 26.3 3.7 5.0 54.6 2001-2002 0.0 0.0 0.0 3.7 T T 0.0 3.7 2000-2001 T 0.0 10.8 9.2 8.6 10.3 T 38.9 1999-2000 0.0 T 0.4 5.8 2.6 0.2 T 9.0 1998-1999 0.0 0.0 3.0 4.5 2.8 9.1 T 19.4 1997-1998 0.0 T 1.0 T T 1.6 T 2.6 1996-1997 0.0 T 1.2 3.3 2.2 3.7 2.0 12.4 1995-1996 0.0 3.0 13.3 20.2 19.0 12.0 9.6 77.1 1994-1995 0.0 T T T 5.1 T 0.0 5.1 1993-1994 0.0 T 3.3 8.8 20.0 5.0 0.0 37.1 1992-1993 0.0 0.0 2.1 2.3 10.9 13.3 0.0 28.6 1991-1992 0.0 0.0 2.0 2.3 1.5 7.6 T 13.4 1990-1991 0.0 0.0 4.0 3.6 4.3 1.9 0.0 13.8 Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season 1989-1990 0.0 7.6 0.2 2.0 2.0 4.2 3.0 19.0 1988-1989 0.0 0.0 10.4 4.4 1.2 3.0 T 19.0 1987-1988 0.0 1.1 4.2 10.7 0.1 3.4 0.0 19.5 1986-1987 0.0 T 3.4 8.8 8.6 1.7 0.0 22.5 1985-1986 0.0 T 2.1 2.6 10.4 0.1 T 15.2 1984-1985 0.0 T 4.7 13.5 8.7 T T 26.9 1983-1984 0.0 T 2.6 11.9 T 13.0 0.0 27.5 1982-1983 0.0 0.0 3.2 1.5 26.1 T 1.1 31.9 1981-1982 0.0 0.0 1.0 18.1 0.3 T 16.0 35.4 1980-1981 0.0 T 0.5 13.2 T 7.1 0.0 20.8 1979-1980 T 0.0 1.5 4.0 1.5 2.0 0.0 9.0 1978-1979 0.0 4.0 T 6.9 17.2 T T 28.1 1977-1978 0.0 0.8 0.2 27.7 28.9 10.4 T 68.0 1976-1977 0.0 T 6.2 11.2 6.6 4.0 0.0 28.0 1975-1976 0.0 T 11.0 7.8 7.5 3.9 0.0 30.2 1974-1975 0.0 0.5 T 1.8 11.0 1.2 T 14.5 1973-1974 0.0 0.0 T 9.0 17.0 8.0 T 34.0 1972-1973 T 0.0 T 1.5 3.0 T T 4.5 1971-1972 0.0 T T 2.1 12.5 1.0 T 15.6 1970-1971 0.0 0.0 2.1 11.3 2.0 1.0 2.5 18.9 1969-1970 0.0 T 12.0 7.0 7.0 1.0 T 27.0 1968-1969 0.0 T 3.0 T 19.5 11.0 0.0 33.5 1967-1968 0.0 2.5 5.0 9.1 3.0 3.0 0.0 22.6 1966-1967 0.0 0.0 8.6 1.0 19.5 21.7 T 50.8 1965-1966 0.0 0.0 T 12.1 3.6 0.0 0.0 15.7 1964-1965 0.0 0.0 2.0 24.6 7.4 4.5 1.0 39.5 1963-1964 0.0 T 11.0 11.7 16.0 1.0 0.0 39.7

We appreciate all the different voices and levels of experience here. That’s what makes this such a unique forum. The one truth about all monthly analogs is that they aren’t revealed to us until the month is nearly over. When analogs are discussed, we are just presenting a range of possibilities that have happened in the recent past. Plus in our warmer climate, analogs older than 10 years or so seldom work out.

That’s why cold is so important this time of year. A marginal or warm airmass for the coast can be fine over the interior parts of the forum. The December average snowfall since the super El Niño in those areas is about double that of NYC. Monthly Total Snowfall for PORT JERVIS, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 7.4 7.4 2021 2.5 2.5 2020 12.8 12.8 2019 9.0 9.0 2018 1.0 1.0 2017 13.0 13.0 2016 13.5 13.5 2015 0.0 0.0 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 3.4 3.4 2021 0.2 0.2 2020 10.5 10.5 2019 2.5 2.5 2018 T T 2017 7.7 7.7 2016 3.2 3.2 2015 T T

We won’t know for sure unless one of these day 15 forecasts can make it to day 8-10. Notice how the EPS and GEFS keep underestimating the -PNA days 11-15. Now that the period is day 8-10 and the -AO ridge is building down into New England with a deeper -PNA trough over the Western US and Canada. Anytime the ensembles have a ridge axis day 15 in the Aleutians we can count on the -PNA verifying lower. New 204 hr Old 360 hr

NYC got only 0.2” in December 2012 and ISP 0.5”. There was one snow event on the 26th. There were a few inches just west of I-95 and more up in Orange County.

The BNL tower thermometer shows how shallow these radiational cooling inversions are. Near 40° at 50m and around 20° at 2m. So go up about 16 stories above the pine barrens and the temperature is similar to the heat island in NYC.

The answer for NYC snowfall is that a-3 to -4 SD AO in December depends on the Pacific. We had a 10”+ snowstorm in 2020 with the lowest monthly AO reaching -3.197. But that month featured a strong +PNA. NYC got under 1” in December 2012 with a -3.902 lowest AO reading. The Pacific stayed too hostile with a -PNA. Both years featured a SSW event in January and great February snowstorms. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.index.b500101.current.ascii 10.5 “ snow in NYC 0.3 snow in NYC

Stronger systems will tend to hug coast with coastal rains and potential interior higher elevation snows. Weaker systems will get suppressed or sheared due to the stronger -NAO and fast Pacific flow. So the actual storm track might not matter that much for snow near the coast. Not much in the way of cold air next 10 days on the EPS.

I will give the models credit for getting the -NAO and -AO pattern correct. But both the GEFS and EPS have been underestimating the strength of the -PNA trough days 11-15. So we could have another warmer than average December if the cooldown keeps getting pushed back. New 240 hr forecast for 12-14 Old 360 hr forecast 12-14

The RadarScope app has all the airport radars like TJFK and TEWR.

First half of December should be several degrees warmer than average as the fast Pacific flow and -PNA keep temperatures mild.

That’s the well known CFS cold bias with the blue line at the very bottom. It’s not meant to be a temperature forecasting tool. I am not sure why the CFS is even run anymore since the long range seasonal forecasts are very inaccurate. https://www.emc.ncep.noaa.gov/users/verification/global/gfs/ops/grid2grid_all_models/bias/

They are a great resource to show what is going on around the airports with a shorter range. I can remember one of NWS Mets commenting on using them during a severe storm outbreak to supplement the NWS radar. Since the radar echoes with snow were so intense during Nemo, they wrote a whole study on them. Maybe there was a location between spotter measurements that picked up 7-8” inches in one hour. But with all the drifting, we may never be able to know for sure. I have heard 6” per hour rates. But there are always gaps between observations. https://journals.ametsoc.org/view/journals/wefo/29/6/waf-d-14-00056_1.xml Abstract On 8–9 February 2013, the northeastern United States experienced a historic winter weather event ranking among the top five worst blizzards in the region. Heavy snowfall and blizzard conditions occurred from northern New Jersey, inland to New York, and northward through Maine. Storm-total snow accumulations of 30–61 cm were common, with maximum accumulations up to 102 cm and snowfall rates exceeding 15 cm h−1. Dual-polarization radar measurements collected for this winter event provide valuable insights into storm microphysical processes. In this study, polarimetric data from the Weather Surveillance Radar-1988 Doppler (WSR-88D) in Upton, New York (KOKX), are investigated alongside thermodynamic analyses from the 13-km Rapid Refresh model and surface precipitation type observations from both Meteorological Phenomena Identification Near the Ground (mPING) and the National Weather Service (NWS) Forecast Office in Upton, New York, for interpretation of polarimetric signatures. The storm exhibited unique polarimetric signatures, some of which have never before been documented for a winter system. Reflectivity values were unusually large, reaching magnitudes >50 dBZ in shallow regions of heavy wet snow near the surface. The 0°C transition line was exceptionally distinct in the polarimetric imagery, providing detail that was often unmatched by the numerical model output. Other features include differential attenuation of magnitudes typical of melting hail, depolarization streaks that provide evidence of electrification, nonuniform beamfilling, a “snow flare” signature, and localized downward excursions of the melting-layer bright band collocated with observed transitions in surface precipitation types. In agreement with previous studies, widespread elevated depositional growth layers, located at temperatures near the model-predicted −15°C isotherm, appear to be correlated with increased snowfall and large reflectivity factors ZH near the surface.

Nemo had an amazing coverage of 30”+ amounts around the region. But those amounts were restricted to east of NYC. It was one of the few times just getting 10”-20” was a disappointment. CONNECTICUT ...FAIRFIELD COUNTY... FAIRFIELD 35.0 1000 AM 2/09 PUBLIC STRATFORD 33.0 1030 AM 2/09 PUBLIC MONROE 30.0 900 AM 2/09 SKYWARN SPOTTER BRIDGEPORT 30.0 658 AM 2/09 COOP OBSERVER MIDDLESEX COUNTY... EAST HADDAM 35.5 845 AM 2/09 PUBLIC OLD SAYBROOK 30.0 1200 PM 2/09 CT DOT NEW HAVEN COUNTY... HAMDEN 40.0 100 PM 2/09 PUBLIC MILFORD 38.0 615 AM 2/09 PUBLIC CLINTONVILLE 37.0 1040 AM 2/09 SKYWARN SPOTTER OXFORD 36.2 600 AM 2/09 SKYWARN SPOTTER NORTH BRANFORD 36.0 1100 AM 2/09 PUBLIC MERIDEN 36.0 200 PM 2/09 PUBLIC YALESVILLE 35.0 909 AM 2/09 SKYWARN SPOTTER WALLINGFORD 35.0 700 AM 2/09 PUBLIC NEW HAVEN 34.3 600 AM 2/09 CT DOT WEST HAVEN 34.0 1040 AM 2/09 PUBLIC NORTHFORD 33.5 950 AM 2/09 SKYWARN SPOTTER WOLCOTT 33.0 457 AM 2/09 SKYWARN SPOTTER EAST HAVEN 33.0 1005 AM 2/09 SKYWARN SPOTTER GUILFORD 33.0 1113 AM 2/09 BROADCAST MEDIA NORTH GUILFORD 32.0 900 AM 2/09 SKYWARN SPOTTER WATERBURY 32.0 900 AM 2/09 PUBLIC MADISON 32.0 321 AM 2/09 PUBLIC NAUGATUCK 30.0 600 AM 2/09 PUBLIC NEW LONDON COUNTY... COLCHESTER 31.0 1200 PM 2/09 CT DOT

Nemo was the only snowstorm since the Doppler radars came out to have a 50 dbz snow band near our area. https://www.washingtonpost.com/blogs/capital-weather-gang/post/incredible-imagery-from-the-february-8-9-2013-new-england-blizzard/2013/02/11/b51df444-73f1-11e2-aa12-e6cf1d31106b_blog.html