bluewave

Our Arctic outbreaks have become much shorter since Valentines Day in 2016. Much more limited supply of Arctic air since then. The aerial coverage of the cold is also much smaller. But we can still get short but sharp Arctic shots from time to time.

One of the coldest air masses at 850 mb to enter New England.

I guess the one similarity is getting a more Nino-like coldest winter temperature in February. We also got our biggest snow of the season this month. So more of a backloaded winter than we normally see during a La Niña. El Niño years with coldest winter readings in February. Monthly Lowest Min Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Season 2022-2023 7 28 26 7 2015-2016 34 11 -1 -1 2014-2015 24 8 2 2 2006-2007 18 9 8 8 1994-1995 19 15 6 6 1986-1987 19 8 4 4 1977-1978 13 12 10 10 1972-1973 19 10 7 7 1957-1958 18 12 3 3

Looks like some of the coldest 850 mb temperatures for this time of year in New England since 1979.

These brief Arctic shots in a sea of warm have become the norm. This should be the coldest February reading after such a warm January. Then we get a quick rebound back to we’ll above average. Time Series Summary for WESTCHESTER CO AP, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature February Min Temp 1 2023 40.0 ? 2 1990 36.9 4 3 2006 36.5 13 4 2017 35.6 15 - 2002 35.6 15 5 1998 35.4 12

The latest Euro gets the 0° line down to near White Plains tomorrow morning. It would be a top 10 coldest reading for February. Also has NYC dipping below 5°. Time Series Summary for WESTCHESTER CO AP, NY - Month of Feb Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1979 -10 0 2 1961 -7 1 3 1967 -6 1 4 2015 -5 0 5 1963 -4 0 6 2016 -3 0 - 1955 -3 1 7 1962 -2 1 8 1958 -1 0 9 1996 0 9 - 1993 0 0 - 1987 0 2

Another one of these brief but impressive Arctic shots in a sea of warm like around Christmas with single digit lows.

A record breaking 8 warmer than normal winters in a row since the 15-16 super El Niño. NYC Jan 23…+9.8 Dec 22…-0.6 …………..+4.6 Feb 22….+1.4 Jan 22….-3.2 Dec 21….+4.7 ……………..+1.0 Feb 21….-1.1 Jan 21….+2.2 Dec 20…+1.7 …………..+0.9 Feb 20…+4.8 Jan 20….+6.5 Dec 19….+0.8 …………….+4.0 Feb 19….+0.9 Jan 19….-0.1 Dec 18…+2.6 …………….+1.1 Feb 18…+6.7 Jan 18….-0.9 Dec 17…..-2.5 …………….+1.1 Feb 17…..+6.3 Jan 17….+5.4 Dec 16….+0.8 …………….+4.2 Feb 16….+2.4 Jan 16….+1.9 Dec 15….+13.3 …………….+5.9

Just goes to show how difficult it is to go a whole season without measurable snow even in a warming climate.

JFK ties for the latest first measurable snowfall. First/Last Summary for JFK INTERNATIONAL AIRPORT, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Difference 1972 03-14 (1972) 1.9 01-29 (1973) 0.8 320 1965 04-02 (1965) 1.4 01-23 (1966) 1.8 295 2006 04-05 (2006) 1.0 01-19 (2007) 0.4 288 1994 03-18 (1994) 2.2 01-11 (1995) 0.1 298 2001 03-26 (2001) 1.7 01-07 (2002) 0.4 286

All our major stations will finish January at or near the warmest on record. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 43.9 3 2 1932 42.0 0 3 1990 40.4 0 4 1950 40.3 0 5 1998 40.1 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 43.2 3 - 1932 43.2 0 2 1950 41.8 2 3 1990 41.4 0 4 2006 40.9 0 5 1913 40.8 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 43.1 3 2 2006 41.5 0 3 1950 41.2 0 4 1990 41.1 0 5 2002 40.4 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 41.8 3 2 1950 40.5 0 3 1998 39.6 0 4 1990 39.4 0 5 2006 39.1 0 6 2002 38.9 0 Time Series Summary for WESTCHESTER CO AP, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 39.9 3 2 1990 36.9 1 3 2006 36.5 0 4 2017 35.6 1 - 2002 35.6 0 5 1998 35.4 11 Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 39.9 3 2 2017 36.9 0 3 1950 36.8 0 4 2020 36.7 0 - 1998 36.7 0 - 1990 36.7 0 5 2006 36.6 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 41.3 3 2 1998 39.1 0 3 1995 38.0 0 4 1990 37.9 0 5 2002 37.7 0

Yeah, with a brief cool down next weekend. KNYC GFSX MOS GUIDANCE 1/28/2023 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 SAT 28| SUN 29| MON 30| TUE 31| WED 01| THU 02| FRI 03| SAT 04 CLIMO X/N 52| 40 52| 41 50| 31 39| 25 39| 30 42| 32 40| 15 28 24 39

Impressive number of stations averaging near or over 40° in January. This is why there are so many stations close to the warmest January on record. So numerous +10s around the area. Data for January 1, 2023 through January 28, 2023 Click column heading to sort ascending, click again to sort descending. State Name Station Type Mean Avg Temperature NJ NEWARK LIBERTY INTL AP WBAN 44.0 NY NY CITY CENTRAL PARK WBAN 43.2 NY MONTAUK AIRPORT WBAN 43.1 NY LAGUARDIA AIRPORT WBAN 43.0 NY FARMINGDALE REPUBLIC AP WBAN 42.3 NJ HARRISON COOP 42.1 NY BAITING HOLLOW COOP 41.9 NY JFK INTERNATIONAL AIRPORT WBAN 41.8 CT NEW HAVEN TWEED AP WBAN 41.6 NY ORIENT POINT STATE PARK COOP 41.4 NY ISLIP-LI MACARTHUR AP WBAN 41.3 NY RIVERHEAD RESEARCH FARM COOP 41.3 NJ TETERBORO AIRPORT WBAN 41.2 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 41.2 NJ CALDWELL ESSEX COUNTY AP WBAN 41.0 CT GROTON NEW LONDON AP WBAN 41.0 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 39.9 NY WESTCHESTER CO AP WBAN 39.9 NY CENTERPORT COOP 39.8 NY SYOSSET COOP 39.8 NY WESTHAMPTON GABRESKI AP WBAN 39.7 CT DANBURY MUNICIPAL AP WBAN 39.4 NY BRIDGEHAMPTON COOP 39.4 NY UPTON COOP - NWSFO NEW YORK COOP 39.0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2023 44.0 4 2 1932 42.0 0 3 1990 40.4 0 4 1950 40.3 0 5 1998 40.1 0 6 2006 39.6 0 7 2002 39.4 0 8 1937 39.0 0 9 1933 38.8 0 10 2020 38.7 0

Yeah, several new all-time rainfall records associated with that warm pool.

All our local stations had a 5 year moving average near 40”. Islip did the best around 50”. It was closer to all the benchmark tracks.

Yeah, the low of 20° so far at a more rural station like Port Jervis is the warmest on record for January. It was 3° warmer than any previous January. Same for the urbanized NYC which only fell to 28° which was also 3° warmer than any other year. A more rural White Plains at the airport only dropped to 27° which was 5° warmer than the previous warmest. Time Series Summary for PORT JERVIS, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2023 20 4 2 1990 17 0 3 1932 16 1 4 1937 12 0 5 1913 11 1 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2023 28 4 2 1937 25 0 3 1990 24 0 - 1932 24 0 4 2002 21 0 - 1993 21 0 - 1953 21 0 5 2020 20 0 - 1949 20 0 Time Series Summary for WESTCHESTER CO AP, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 2023 26 4 2 1990 21 1 3 1953 18 0 4 1993 17 2 5 2002 16 0

The funny thing is that math was my least favorite subject back in school. But I have always been fascinated by all types of patterns in nature. So this interest in weather and climate statistics is more recent.

That’s the NYC DJF mean temperature trend. So the winter of 76-77 was correct. It was our last top 10 coldest winter. 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

The longer term decline would be more pronounced if the snowfall measurements were taken as frequently as today. https://news.ucar.edu/14009/snowfall-measurement-flaky-history Earlier in our weather history, the standard practice was to record snowfall amounts less frequently, such as every 12 or 24 hours, or even to take just one measurement of depth on the ground at the end of the storm. You might think that one or two measurements per day should add up to pretty much the same as measurements taken every 6 hours during the storm. It’s a logical assumption, but you would be mistaken. Snow on the ground gets compacted as additional snow falls. Therefore, multiple measurements during a storm typically result in a higher total than if snowfall is derived from just one or two measurements per day. That can make quite a significant difference. It turns out that it’s not uncommon for the snow on the ground at the end of a storm to be 15 to 20 percent less than the total that would be derived from multiple snowboard measurements. As the cooperative climate observer for Boulder, Colorado, I examined the 15 biggest snowfalls of the last two decades, all measured at the NOAA campus in Boulder. The sum of the snowboard measurements averaged 17 percent greater than the maximum depth on the ground at the end of the storm. For a 20-inch snowfall, that would be a boost of 3.4 inches—enough to dethrone many close rivals on the top-10 snowstorm list that were not necessarily lesser storms! Another common practice at the cooperative observing stations prior to 1950 did not involve measuring snow at all, but instead took the liquid derived from the snow and applied a 10:1 ratio (every inch of liquid equals ten inches of snow). This is no longer the official practice and has become increasingly less common since 1950. But it too introduces a potential low bias in historic snowfalls because in most parts of the country (and in the recent blizzard in the Northeast) one inch of liquid produces more than 10 inches of snow. This means that many of the storms from the 1980s or earlier would probably appear in the record as bigger storms if the observers had used the currently accepted methodology. Now, for those of you northeasterners with aching backs from shoveling, I am not saying that your recent storm wasn’t big in places like Boston, Portland, or Long Island. But I am saying that some of the past greats—the February Blizzard of 1978, the Knickerbocker storm of January 1922, and the great Blizzard of March 1888—are probably underestimated. So keep in mind when viewing those lists of snowy greats: the older ones are not directly comparable with those in recent decades. It’s not as bad as comparing apples to oranges, but it may be like comparing apples to crabapples.

It’s possible that the 5 year moving average getting above 40” in NYC during the 2010s may have been a short term peak within a long term decline.

The day 11-15 model forecasts keep underestimating the influence of the record warm pool to our east. https://frontierweather.dtn.com/verification.html

The slowing AMOC is enhancing the warming pattern. It allows the warm waters to pile up along the East Coast. The only part of the globe that is cooling from this is localized area south of Greenland.

Yeah, the warming Gulf Stream and Western Pacific are probably our two most important climate influences since 2015-2016. They both reinforce a more La Niña-like pattern. So we get the dominant SE Ridge pattern.

The other possibility is that the record breaking SE Ridge since 2015 is being forced by climate change. So it could turn out to be a new climate change teleconnection. Record Gulf Stream warmth combined with record MJO 4-6 warm pool in the WPAC.

Starting to look like 2013 to 2018 was our snowfall peak before the decline began in 2019. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.0 0.8 3.5 14.2 12.2 8.0 0.9 39.6 2017-2018 0.0 T 7.7 11.2 4.9 11.6 5.5 40.9 2016-2017 0.0 T 3.2 7.9 9.4 9.7 0.0 30.2 2015-2016 0.0 0.0 T 27.9 4.0 0.9 T 32.8 2014-2015 0.0 0.2 1.0 16.9 13.6 18.6 0.0 50.3 2013-2014 0.0 T 8.6 19.7 29.0 0.1 T 57.4 2012-2013 0.0 4.7 0.4 1.5 12.2 7.3 0.0 26.1 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.0 1.3 2.6 4.2 7.7 2.7 T 16.4 2022-2023 0.0 0.0 T T M M M T 2021-2022 0.0 T 0.2 15.3 2.0 0.4 0.0 17.9 2020-2021 0.0 0.0 10.5 2.1 26.0 T 0.0 38.6 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 2018-2019 0.0 6.4 T 1.1 2.6 10.4 0.0 20.5 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 Mean T 0.8 3.1 19.9 16.4 12.5 0.8 53.5 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 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 Mean T 0.9 2.5 7.3 7.9 1.4 T 18.1 2022-2023 0.0 0.0 0.4 T M M M 0.4 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