bluewave

NYC will have a shot at the first single digits of the season next week. Models starting to more of a W to WSW flow which moves south of the Great Lakes. But if the flow is too much from the SW then NYC may struggle to get much under 10°. So the wind direction will play a big role in how cold we get since the Great Lakes are still so warm. The Great Lakes were so cold and Erie was often frozen over in the 1970s to early 1990s that NYC could go below 0° with flow across the Great Lakes. These days NYC generally needs a N to NW flow down the Hudson Valley for its coldest readings. It’s interesting how 22-23 was one of our warmest winters but NYC was still able to get down to 3° in early February since the N to NW flow avoided the warm Great Lakes. Same went for another warmest winter in 15-16 when NYC went below 0° on a NNW cold air drain down the Hudson Valley. So it will be funny if the NYC low ends up higher than in February 2023 even though this winter has been a colder one than that one through mid to late January.

Boston had more snow in one month back in 2015 than all the snow since December 2021. Maximum 30-Day Total Snowfall for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 94.4 2015-02-22 0 Time Series Summary for Boston Area, MA (ThreadEx) - Oct through Sep Click column heading to sort ascending, click again to sort descending. 2024-2025 7.5 2023-2024 9.8 0 2022-2023 12.4 0 2021-2022 54.0 0 2020-2021 38.6 0 2019-2020 15.8 0 2018-2019 27.4 0

19-20 to 20-24 was the first time that the Boston 5 year moving average snowfall dipped down to only 25.1”. The lowest of the 1980s was 31.1”. So the persistent cutter, hugger, and suppressed Southern Stream storm tracks since 18-19 is really being felt across the region. We will need a return of the KU BM storm tracks before 28-29 in order to avoid the least snowiest decade on record for spots across the region.

Having the 1st half of winter finish closer to average across the Northeast feels much colder given the record warmth last few winters plus the very windy conditions this month.

The long term snowfall in the South is declining. But since the bar is lower for average there, it’s easier for an event or two to reach average. So if you average less than 10” annually, it doesn’t take much to have an occasional average to above average season. This is like what happened during May 2020 in NYC. All it took was a T to tie the previous snowiest May on record in 1977. May 2020 was the only month in NYC since 2018-2019 with a new snowiest month or tie of a previous snowiest month.

Philly is similar to our area since the 90s in needing KU storms that pass within a certain distance of the BM in order to reach 20” on the season. Before the 90s seasons could get either KUs or more moderate events and still reach 20”. So with all the cutter, hugger, and suppressed Southern Stream storm tracks since 18-19, only 20-21 made it over 20” with the great KU storm tracks that winter. 2022 was a little too wide of the BM to the south and east which favored ACY. So the lack of BM KU events in recent years where some part of the region gets a 10”+ jackpots has resulted in the 2020s starting off as the least snowiest decade in several spots. So we will need to see a big storm track improvement back to the BM going forward for the 19-20 to 20-29 to avoid becoming the least snowiest decade across the region.

The record warmth in December 2015. Monthly Mean Min Temperature for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. 2015-2016 44.2 27.6 30.1 34.0

11-12 got pushed further back in the pack after all the warmth since then. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending average winter low temperature 1 2015-2016 34.0 0 2 2001-2002 33.5 0 3 2016-2017 33.2 0 4 2023-2024 33.0 0 - 1997-1998 33.0 0 5 2011-2012 32.7 0 6 1982-1983 32.6 0 7 2022-2023 32.5 0 8 1974-1975 32.2 0 - 1952-1953 32.2 0 9 2019-2020 32.1 0

14-15 was the only season with so many days having 1” OTG following a top 5 warmest Christmas high temperature. Data for December 25 - JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. 2015-12-25 64 52 0.10 0.0 0 2020-12-25 60 29 0.59 0.0 0 1982-12-25 58 42 0.01 0.0 0 2014-12-25 57 42 0.06 0.0 0 2008-12-25 57 32 0.06 0.0 0 1994-12-25 57 41 T 0.0 0 1964-12-25 56 42 0.02 0.0 0

Anything at or above 32 days for JFK qualifies for the 10 highest number of days with 1” of snow OTG. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Oct through Sep Click column heading to sort ascending, click again to sort descending. 1 1995-1996 50 0 2 2014-2015 48 0 3 1977-1978 44 0 4 2002-2003 43 0 - 1960-1961 43 1 5 2010-2011 41 0 6 1976-1977 38 0 7 2004-2005 36 0 8 2000-2001 35 0 9 2013-2014 34 0 - 1963-1964 34 0 10 1993-1994 32 0

The nighttime temperatures in NW New Jersey have been warmer for average for January so far. The one time they got really cold was right before Christmas. That was when we had the great radiational cooling with the record high pressure. So there was no flow across the Great Lakes.

So far the Northeast temperatures have been running near average since the beginning of December. Slightly below average temperatures in December and a little above average for January so far. The cold coming in from the 20th to 25th will result in the December 1st through January 25th average temperature departure running below average. The Northeast has had numerous years that were much colder than this since the 90s through the first half of winter. So whether this winter will be the first colder one in the Northeast in 10 years will depend on the February departure. The combination of record warmth in Canada leading to the delayed freeze-up on Hudson Bay and record Great Lakes warmth has lead to the Northeast departures running warmer than the Mid-Atlantic. Plus this is against the warmest 1991-2020 climate normals. If we were using 1981-2010 climate normals then the Northeast would be warmer than average for the 1st half of the winter. So depending on February the Northeast could finish the winter below average using 1991-2020 climate normals and above average vs 1981-2010 normals. But if the February temperature departures are wam enough, then the Northeast will finish above average again.

76-77 was the 8th coldest winter temperature on record for NYC since 1870. It was the last time NYC had a top 10 coldest winter at 28.4°. 93-94 was the 20th coldest winter temperature at 31.1°. 14-15 was the 22nd coldest winter at 31.4° and the last time NYC had a winter average under 32.0°. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 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 23 1898-1899 31.5 0 24 1939-1940 31.6 0 - 1906-1907 31.6 0 25 1960-1961 31.7 0 - 1916-1917 31.7 0 - 1900-1901 31.7 0 26 1913-1914 31.9 0

76-77 was the coldest winter on record for JFK with an average temperature of 28.0°. So even though the snowfall total was only 22.7” for the season, JFK was able have 38 days with 1” of snow depth. It was the only time JFK had 35+ days with 1” OTG and under 33.8” on the season. 76-77 was one of those winters from a colder era when we could get numerous smaller and one moderate event and have a snowfall total in the 20s without someone in the area getting a big KU and 10”+ totals. The heaviest snowfall that winter was a 4-6” moderate event in mid-January. Data for January 14, 1977 through January 15, 1977 Click column heading to sort ascending, click again to sort descending. NY MINEOLA COOP 6.5 NY ISLIP-LI MACARTHUR AP WBAN 6.3 NY NEW YORK AVE V BROOKLYN COOP 6.0 NY NY WESTERLEIGH STAT IS COOP 6.0 NJ TETERBORO AIRPORT WBAN 6.0 NY SCARSDALE COOP 6.0 NY MARYKNOLL COOP 5.9 NY RIVERHEAD RESEARCH FARM COOP 5.8 NY JFK INTERNATIONAL AIRPORT WBAN 5.6 NY PATCHOGUE 2 N COOP 5.5 NJ PLAINFIELD COOP 5.2 NY NY CITY CENTRAL PARK WBAN 5.2 NJ CRANFORD COOP 5.0 NJ CANOE BROOK COOP 5.0 NJ MAHWAH COOP 5.0 NY BRIDGEHAMPTON COOP 5.0 NY LAGUARDIA AIRPORT WBAN 4.8 NY DOBBS FERRY-ARDSLEY COOP 4.7 NJ NEWARK LIBERTY INTL AP WBAN 4.5 NJ LITTLE FALLS COOP 4.5 NJ CHARLOTTEBURG RESERVOIR COOP 4.5 NY BEDFORD HILLS COOP 4.5 NY SETAUKET STRONG COOP 4.5 NY WESTCHESTER CO AP WBAN 4.3

CRW is actually colder than ALB which is pretty rare in early January. CRW…..25.3°….-9.9° ALB…….26.0°…+0.7°

This is a function of the record Great Lakes warmth combined with lower pressures and stronger winds. So the clouds and wind at night kept the minimum departures up preventing good radiational cooling. More clouds during the day reduced the sunshine with lower maximum temperature departures across the region. But both the maximum and minimum departures were lower further south where the flow didn’t cross the warmer Great Lakes. Plus Eastern Canada has been very warm leading to the delayed freeze-up on Hudson Bay. So multiple ways to get a warmer departure north and colder departure south pattern.

13-14 was a more impressive winter to our west for days with 1” OTG. Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Oct through Sep Click column heading to sort ascending, click again to sort descending days with 1” OTG 1 1995-1996 62 0 2 2004-2005 55 0 3 1977-1978 53 1 4 2014-2015 48 0 5 1993-1994 46 3 6 2010-2011 45 0 7 2013-2014 39 0 - 2000-2001 39 23 8 1964-1965 37 1 9 1976-1977 36 0 10 1963-1964 35 7 11 1969-1970 34 2 12 2009-2010 32 0 13 2020-2021 30 0 - 2017-2018 30 0 14 2008-2009 29 0 - 2003-2004 29 7 15 2012-2013 27 0 Time Series Summary for New Brunswick Area, NJ (ThreadEx) - Oct through Sep Click column heading to sort ascending, click again to sort descending with 1” OTG 1 1995-1996 68 0 2 1977-1978 66 0 3 1993-1994 64 0 4 2013-2014 62 0 5 1947-1948 60 3 6 2010-2011 57 5 - 1935-1936 57 0 7 1960-1961 55 0 - 1917-1918 55 6 8 2014-2015 53 8 - 1919-1920 53 4 9 1976-1977 51 0 10 1933-1934 50 0 11 1969-1970 47 0 - 1944-1945 47 0 12 2002-2003 46 23 13 2000-2001 45 0 14 1986-1987 44 0 - 1922-1923 44 6

Yeah, 50 days with over 1” OTG was a much different pattern compared to recent years. Time Series Summary for New Brunswick Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending days with 1” or more OTG 2025-04-30 9 2024-04-30 16 2023-04-30 0 2022-04-30 12 2021-04-30 37 2020-04-30 4 2019-04-30 11 2018-04-30 28 2017-04-30 18 2016-04-30 18 2015-04-30 53 2014-04-30 62 2013-04-30 13 2012-04-30 6 2011-04-30 57

This January drier period looks more transient compared to the extended dry period from late August into late November.

We have been doing very well east of NYC since the fall dry pattern ended back in late November with 10.00”+ in many areas. Data for November 20, 2024 through January 13, 2025 Click column heading to sort ascending, click again to sort descending. NY MOUNT SINAI COOP 11.42 CT COLCHESTER 0.6 ENE CoCoRaHS 11.30 NY NESCONSET 1.4 SSW CoCoRaHS 11.19 CT EAST LYME 0.5 SW CoCoRaHS 11.15 CT SALEM 3.6 SE CoCoRaHS 11.13 NY ST. JAMES COOP 10.79 NY CENTERPORT COOP 10.77 NY CENTERPORT 1.1 SE CoCoRaHS 10.73 CT PAWCATUCK 1.8 SSE CoCoRaHS 10.73 CT EAST LYME 0.6 N CoCoRaHS 10.73 NY BAITING HOLLOW COOP 10.71 CT PAWCATUCK 0.8 SE CoCoRaHS 10.67 CT STONINGTON 1.4 NNW CoCoRaHS 10.66 CT CHESTER CENTER 2.7 WNW CoCoRaHS 10.63 CT UNCASVILLE-OXOBOXO VALLEY 1.6 ENE CoCoRaHS 10.63 NY SELDEN 1.6 ESE CoCoRaHS 10.48 CT PUTNAM LAKE COOP 10.42 NY PORT JEFFERSON STATION 0.3 SSW CoCoRaHS 10.41 CT HIGGANUM 0.8 NE CoCoRaHS 10.29 NY CENTER MORICHES 0.5 N CoCoRaHS 10.28 NY MANORVILLE 1.8 SSE CoCoRaHS 10.26 NY ISLIP TERRACE 1.1 NNE CoCoRaHS 10.23 CT HIGGANUM 0.7 N CoCoRaHS 10.22 CT OAKDALE 2.6 WNW CoCoRaHS 10.22 CT MYSTIC 1.6 W CoCoRaHS 10.22 CT NEW CANAAN 1.9 ENE CoCoRaHS 10.15 NY ISLIP TERRACE 0.5 W CoCoRaHS 10.14 CT NORTHFORD 0.8 SW CoCoRaHS 10.14 CT NORWICH 5.4 SE CoCoRaHS 10.13 NY SETAUKET-EAST SETAUKET 2.1 WNW CoCoRaHS 10.03 NY UPTON COOP - NWSFO NEW YORK COOP 10.03 NY CENTEREACH 1.3 NE CoCoRaHS 10.03 NY FISHERS ISLAND 0.5 NE CoCoRaHS 9.97 CT MONROE 0.8 W CoCoRaHS 9.96 NY RIVERHEAD RESEARCH FARM COOP 9.88 CT GUILFORD COOP 9.88 NY MALVERNE 0.5 SE CoCoRaHS 9.87 CT NORWICH 5.2 SE CoCoRaHS 9.87 CT JEWETT CITY 3.0 ESE CoCoRaHS 9.86 NY REMSENBURG-SPEONK 0.9 NE CoCoRaHS 9.85 NY SEAFORD 0.4 SE CoCoRaHS 9.79 CT NORWICH 2.5 NNE CoCoRaHS 9.79 CT STONINGTON 0.5 NNE CoCoRaHS 9.73 NY ALBERTSON 0.2 SSE CoCoRaHS 9.72 NY RIDGE 1.5 SE CoCoRaHS 9.72 CT DANBURY COOP 9.72 CT MIDDLEFIELD 1.4 W CoCoRaHS 9.71 CT ESSEX VILLAGE 0.9 S CoCoRaHS 9.70 NY LITTLE NECK 0.3 SE CoCoRaHS 9.69 CT NEW LONDON 1.0 NNW CoCoRaHS 9.68 NY BRIGHTWATERS 0.7 NNW CoCoRaHS 9.67 CT MYSTIC 3.4 NW CoCoRaHS 9.62 NY RIVERHEAD 1.3 SSE CoCoRaHS 9.60 NY MANHASSET HILLS 0.2 NNE CoCoRaHS 9.55 NY HOWARD BEACH 0.4 NNW CoCoRaHS 9.54 CT MOODUS 0.7 SSW CoCoRaHS 9.54 CT FAIRFIELD 1.5 NE CoCoRaHS 9.51 CT GRISWOLD 0.9 N CoCoRaHS 9.49 CT WATERFORD 1.1 E CoCoRaHS 9.47 CT GUILFORD CENTER 2.7 WSW CoCoRaHS 9.43 NY BAY SHORE 0.5 ESE CoCoRaHS 9.41 CT KILLINGWORTH 2.6 ESE CoCoRaHS 9.39 NY MONTAUK AIRPORT WBAN 9.39 NY ISLIP-LI MACARTHUR AP WBAN 9.37 CT NORWALK 2.9 NNW CoCoRaHS 9.35 CT OLD LYME 1.7 NNE CoCoRaHS 9.27 CT RIDGEFIELD 2.4 NNE CoCoRaHS 9.25 CT STAMFORD 1.0 S CoCoRaHS 9.25 CT WALLINGFORD CENTER 1.9 WNW CoCoRaHS 9.24 CT WALLINGFORD CENTER 3.3 NNW CoCoRaHS 9.22 CT MADISON CENTER 1.3 N CoCoRaHS 9.21 CT MYSTIC 0.9 W CoCoRaHS 9.21 CT STRATFORD 0.2 ESE CoCoRaHS 9.18 CT NEW CANAAN 3.8 N CoCoRaHS 9.16 CT NEWTOWN 4.6 SE CoCoRaHS 9.16 CT COLCHESTER 5.5 NNE CoCoRaHS 9.15 CT BETHEL 3.5 NNE CoCoRaHS 9.09 NY JAMESPORT 0.6 SSW CoCoRaHS 9.07 CT NIANTIC 1.1 SW CoCoRaHS 9.07 NJ HARRISON COOP 9.02 NY SAYVILLE 1.0 SSE CoCoRaHS 9.01 CT OLD LYME 3.4 ESE CoCoRaHS 9.01

Maybe the PCC has finally shifted. The record warming started before the El Niño became established in Nino 3.4 during 2023 with that unusually strong WWB closer to Nino 1+2 and record warming there for so early in an El Niño event. While Nino 3.4 has finally been declared to be in La Niña, Nino 1+2 is still having warmer readings with unusual WWB activity there for a La Niña fall into winter. But this new paper may only be scratching the surface in terms of our understanding of how the Pacific can modulate warming on a global scale. So perhaps we need to focus on the unusual events which continue near Nino 1+2 since the late winter back in 2023. https://communities.springernature.com/posts/an-emerging-pacific-climate-change-pattern it might reverse and, even if this meant drought alleviation in the southwest and East Africa, would herald a phase of strong global warming. Our new research supports the first possibility. We identified an emerging climate change signal in the tropical Pacific that we call the Pacific Climate Change (PCC) pattern. This is clearly distinguishable from the decadal variability of the IPO. While the IPO is associated with a meridionally broad, wedge-shaped sea surface temperature (SST) anomaly, the PCC, which has emerged since the mid-1950s, features a narrow band of cooling along the equator with warming elsewhere. The PCC emerges over time while the IPO oscillates back and forth as expected if the PCC is a signal of climate change and the IPO is natural variability. Both the PCC and IPO involve changes in thermocline depth and subsurface temperature in the upwelling regions of the central to eastern equatorial Pacific. Despite this similarity we show, using ocean data and a simple wind-driven ocean model, that the PCC’s atmosphere-ocean dynamics are fundamentally different from those of the IPO.

Looks like January 20 to 27 could be our coldest week of the winter so far. Then we see the La Niña seasonal progression on all the guidance. So the usual La Niña warm up heading into February. EPS Jan 20 to 27 Jan 27 to Feb 3

Those winds were crossing the warmer Great Lakes. Plus Canada still hasn’t cooled off yet from all the record warmth in recent years. This has lead to the delayed freeze-up on Hudson Bay. It looks like Canada is finally forecast to start getting colder next weekend.

They are taking longer than normal to cool down due to recent record warmth and keeping the minimums warmer so far this month in the Northeast.