bluewave

They also put out a separate 15 year climate normals but it’s not as widely used as the 30 years. The main challenge of using climate normals in a rapidly warming climate is that it masks the warming. With the new 39.1 average December temperature in NYC, they only need a +3.4 departure to enter the top 10 warmest of December average temperatures. And we hear the sentiment on here that a +3.4 really isn’t anything out of the ordinary since it’s much lower than the +13.3° and 50° December 2015. Plus we have had something like 20-30 top 10 warmest months of the year depending on the local station used to only one top 10 coldest since 2015. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 50.8 0 2 2001 44.1 0 3 2021 43.8 0 4 1984 43.7 0 5 2006 43.6 0 6 2011 43.3 0 7 1998 43.1 0 8 1982 42.7 0 9 1990 42.6 0 10 1891 42.5 0

I scanned it very quickly and didn’t realize the data was missing. So the most recent decade at BTV is +5.9 warmer than than their earliest 30 year December average. It would probably be closer to +6.7 warmer if they had a complete record that started around 1870 like the NYC comparison which was in a colder era than the earliest available. Monthly Mean Avg Temperature for Burlington Area, VT (ThreadEx) Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 23.6 23.6 1921 20.3 20.3 1920 25.3 25.3 1919 17.2 17.2 1918 25.5 25.5 1917 12.2 12.2 1916 21.6 21.6 1915 25.1 25.1 1914 21.2 21.2 1913 27.0 27.0 1912 29.0 29.0 1911 31.0 31.0 1910 15.9 15.9 1909 21.3 21.3 1908 21.4 21.4 1907 27.0 27.0 1906 17.2 17.2 1905 28.3 28.3 1904 16.0 16.0 1903 20.7 20.7 1902 22.2 22.2 1901 26.1 26.1 1900 24.8 24.8 1899 30.9 30.9 1898 27.6 27.6 1897 27.3 27.3 1896 23.5 23.5 1895 29.0 29.0 1894 28.3 28.3 1893 22.1 22.1 1892 23.1 23.1 Monthly Mean Avg Temperature for Burlington Area, VT (ThreadEx) Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 29.5 29.5 2022 31.6 31.6 2021 31.8 31.8 2020 31.3 31.3 2019 27.4 27.4 2018 26.8 26.8 2017 22.3 22.3 2016 29.0 29.0 2015 39.2 39.2 2014 30.0 30.0 2013 23.5 23.5 2012 30.8 30.8 2011 30.6 30.6

The last decade has been about 6.6° warmer than the late 1800s in December. So we currently have the same December temperatures that used to be common in Virginia in the late 1800s. Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 34.1 34.1 1900 36.2 36.2 1899 38.1 38.1 1898 35.0 35.0 1897 38.6 38.6 1896 34.4 34.4 1895 38.4 38.4 1894 36.7 36.7 1893 34.9 34.9 1892 32.2 32.2 1891 42.5 42.5 1890 30.0 30.0 1889 39.7 39.7 1888 34.7 34.7 1887 33.4 33.4 1886 29.7 29.7 1885 35.3 35.3 1884 33.6 33.6 1883 31.6 31.6 1882 30.6 30.6 1881 39.0 39.0 1880 26.4 26.4 1879 36.8 36.8 1878 33.2 33.2 1877 37.4 37.4 1876 25.0 25.0 1875 33.4 33.4 1874 34.4 34.4 1873 36.7 36.7 1872 26.7 26.7 1871 29.0 29.0 Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 40.7 40.7 2022 38.5 38.5 2021 43.8 43.8 2020 39.2 39.2 2019 38.3 38.3 2018 40.1 40.1 2017 35.0 35.0 2016 38.3 38.3 2015 50.8 50.8 2014 40.5 40.5 2013 38.5 38.5 2012 41.5 41.5 2011 43.3 43.3

All that -AO did was trap mild Pacific air underneath.

It’s tough to use the guidance that far out for exact temperatures and departures. We mostly use it to guess where the areas of above and below normal will be. Like the charts that the CPC puts out each day. Plus we also use it to compare how that forecast period is changing in relation to previous runs. But we know that in the past when we had similar projected 500 mb patterns in late December with fast Pacific flow the warmer days in NYC had highs in the 50s and lows in the upper 30s to around 40. The average split in NYC for late December is 42/32. So that means the warmest days during the period can be over +10. And probably a string of other days near +3 to +5.

Yeah, December 1997 actually started out much cooler than this December. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Mean Avg Temperature Dec 1 to Dec 9 Missing Count 2023-12-09 45.4 0 2022-12-09 45.4 0 2021-12-09 43.2 0 2020-12-09 40.3 0 2019-12-09 37.5 0 2018-12-09 38.0 0 2017-12-09 43.9 0 2016-12-09 42.5 0 2015-12-09 47.4 0 2014-12-09 40.7 0 2013-12-09 42.8 0 2012-12-09 45.4 0 2011-12-09 47.6 0 2010-12-09 35.1 0 2009-12-09 43.0 0 2008-12-09 37.3 0 2007-12-09 32.8 0 2006-12-09 38.6 0 2005-12-09 33.2 0 2004-12-09 43.8 0 2003-12-09 30.9 0 2002-12-09 30.6 0 2001-12-09 53.1 0 2000-12-09 32.1 0 1999-12-09 45.8 0 1998-12-09 56.2 0 1997-12-09 39.2 0

At least 97-98 had a nice snowstorm at the end which NYC didn’t get last winter. So it lived up to a weaker version of the backloaded El Niño expectations. Data for March 22, 1998 through March 22, 1998 Click column heading to sort ascending, click again to sort descending. State Name Station Type Total Snowfall NJ GREENWOOD LAKE COOP 7.0 NY YORKTOWN HEIGHTS 1W COOP 7.0 NJ CHARLOTTEBURG RESERVOIR COOP 6.0 NY WEST POINT COOP 6.0 NY NY CITY CENTRAL PARK WBAN 5.0 NJ WANAQUE RAYMOND DAM COOP 4.8 NJ RINGWOOD COOP 4.8 NJ CANOE BROOK COOP 4.5 NY LAGUARDIA AIRPORT WBAN 4.5 NJ HARRISON COOP 4.5 NY WEST NYACK COOP 4.5 NY MINEOLA 1 NE COOP 4.2 NJ MIDLAND PARK COOP 4.0 NY PORT JERVIS COOP 3.7 NY DOBBS FERRY-ARDSLEY COOP 3.5 NY MINEOLA COOP 3.5 NJ NEWARK LIBERTY INTL AP WBAN 3.1 NY WALDEN 1 ESE COOP 3.0 NY JFK INTERNATIONAL AIRPORT WBAN 2.9 NY NEW YORK AVE V BROOKLYN COOP 2.8 NJ CRANFORD COOP 2.5 NJ WAYNE COOP 2.5 NJ PLAINFIELD COOP 2.3 NY RIVERHEAD RESEARCH FARM COOP 2.0 NY ISLIP-LI MACARTHUR AP WBAN 1.6

The 97-98 winter wasn’t really that warm compared to our recent warmest winters since 11-12. 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 2001-2002 41.5 0 2 2022-2023 41.0 0 - 2015-2016 41.0 0 3 2011-2012 40.5 0 4 1931-1932 40.1 0 5 1997-1998 39.6 0 6 2016-2017 39.3 0 7 2019-2020 39.2 0 8 1990-1991 39.1 0 9 1998-1999 38.6 0 10 1948-1949 38.5 0

We knew the models were going to go into full push back mode with the cooler temperatures in late December once they saw how strong this MJO and jet extension was going to be. Dec 25-Jan 1 New run Old run

That Pacific Trough will be off the charts for the 2nd half of December.

While our warmest December by far was during the 2015 super El Niño, Decembers have been warm regardless of El Niño or La Niña. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature ENSO 1 2015 50.8 El Niño 2 2001 44.1 Neutral following 3 year La Niña 3 2021 43.8 La Niña 4 1984 43.7 La Niña 5 2006 43.6 El Niño 6 2011 43.3 La Niña 7 1998 43.1 La Niña 8 1982 42.7 El Niño 9 1990 42.6 Neutral 10 1891 42.5 Neutral 11 1994 42.2 El Niño 12 1923 42.0 El Niño 13 2012 41.5 Neutral 14 1996 41.3 Neutral - 1953 41.3 El Niño 15 1979 41.1 El Nino 16 1956 40.9 Neutral - 1931 40.9 Neutral 17 1971 40.8 La Niña 18 2014 40.5 El Niño - 1965 40.5 El Niño 19 1957 40.2 El Niño 20 2018 40.1 Uncoupled El Niño

The 5 day period around St. Patrick’s Day since 2011 has been much snowier in NYC than the five day period around Christmas. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Mar 12 to Mar 22 Missing Count 2022-03-22 T 0 2021-03-22 T 0 2020-03-22 0.0 0 2019-03-22 0.0 0 2018-03-22 8.4 0 2017-03-22 7.6 0 2016-03-22 0.5 0 2015-03-22 4.5 0 2014-03-22 0.0 0 2013-03-22 3.3 0 2012-03-22 0.0 0 2011-03-22 T 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 20 to Dec 30 Missing Count 2022-12-30 T 0 2021-12-30 0.2 0 2020-12-30 T 0 2019-12-30 T 0 2018-12-30 T 0 2017-12-30 0.7 0 2016-12-30 T 0 2015-12-30 T 0 2014-12-30 T 0 2013-12-30 T 0 2012-12-30 0.4 0 2011-12-30 0.0 0

Main issue is that trough in the Southeast is filled with mild Pacific air following the big jet extension.

I never said that it can’t snow. But those warm anomalies have resulted in North American snow cover dipping to decadal lows for early December.

The greatest winter warming over the last 75 year has been in the Upper Midwest. The good news for Great Lakes snow lovers is that the warmer lakes staying open longer are producing heavier lake effect snows. But the bad news is that the ice fishing season is getting shorter across the Upper Midwest.

The volatility in the snowfall has been well documented since the 90s in terms of more all or nothing snowfall seasons especially at the Long Island stations to the east like Islip. The drop in snowfall began with the 18-19 season. So this is a relatively recent down turn lasting only about 5 years. The previous 5 year period was among the snowiest on record especially on Long Island. The current warm winter streak has been unprecedented in the entire record. We have never experienced 8 warmer than normal winters in a row with so many months landing in the top 10 warmest. Also some of the individual monthly records like the +13.3 December 2015 and the 80° at Newark in February 2018 has never happened before. So the warmth has been remarkable for both the departures and the actual temperatures. Plus the departures are against the warmer climate period since the 90s. NYC Feb 23…+5.2 Jan 23…+9.8 Dec 22…-0.6 …………..+4.8 Feb 22….+1.4 Jan 22….-3.2 Dec 21….+4.7 ……………..+1.0 Feb 21….-1.7 Jan 21….+1.1 Dec 20…+1.7 …………..+0.4 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

That’s one of the weaknesses with the entire online meteorological community on twitter. We really have to dig into why the models are showing a particular outcome and try to anticipate where the bias lies. My focus has been trying to identify model biases and taking things from there. That’s the main reason I have been anticipating warmer risks from mid to late December than any of the models were showing. Big meteorology firms don’t realize how much money they are leaving on the table by just relying on the actual long range model output without trying to anticipate what the model errors are.

But the long term convection is increasing faster over the parts of the oceans which contain the warmest MJO phases.

That the warming of the Western Pacific loads the dice for warmer winter outcomes in our area.

I began to suspect it after seeing the extreme warmth in December 2015 when we had a record MJO 5 for a super El Niño. But we recently got confirmation in 2019 that this is the case. It’s not just chance that we have had 8 warmer than normal winters in a row which never happened before. https://www.nature.com/articles/s41586-019-1764-4 Twofold expansion of the Indo-Pacific warm pool warps the MJO life cycle M. K. Roxy, Panini Dasgupta, Michael J. McPhaden, Tamaki Suematsu, Chidong Zhang & Daehyun Kim Nature volume 575, pages 647–651 (2019)Cite this article 12k Accesses 91 Citations 498 Altmetric Metrics details Abstract The Madden–Julian Oscillation (MJO) is the most dominant mode of subseasonal variability in the tropics, characterized by an eastward-moving band of rain clouds. The MJO modulates the El Niño Southern Oscillation1, tropical cyclones2,3 and the monsoons4,5,6,7,8,9,10, and contributes to severe weather events over Asia, Australia, Africa, Europe and the Americas. MJO events travel a distance of 12,000–20,000 km across the tropical oceans, covering a region that has been warming during the twentieth and early twenty-first centuries in response to increased anthropogenic emissions of greenhouse gases11, and is projected to warm further. However, the impact of this warming on the MJO life cycle is largely unknown. Here we show that rapid warming over the tropical oceans during 1981–2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900–2018 and at an accelerated average rate of 4 × 105 km2(the size of California) per year during 1981–2018. The changes in the Indo-Pacific warm pool and the MJO are related to increased rainfall over southeast Asia, northern Australia, Southwest Africa and the Amazon, and drying over the west coast of the United States and Ecuador

Especially with the bias corrected charts.

Higher ocean heat content is increasing the convection in the warmer MJO phases.

It doesn’t matter anymore whether we have an El Niño like this December or a La Niña like last January. We keep getting these ridiculous Pacific Jet extensions that bring record warmth to North America. My guess is that all the warmth in the Western to Central Pacific MJO regions are driving this phenomenon. This time with the orientation in the ridge, the warmest departures will probably line up further west than last January. But even in a warming planet, it’s noteworthy to get two consecutive winters with monthly departures so high for the North American continent.

I don’t mind the back and forth as long as people leave the personal digs out of the picture. We can have disagreements without being nasty about it. I actually started my early online weather explorations by becoming a contributor to the old Weatherpoint Counterpoint shows back on Accuweather with JB and the late Ken Reeves. As much as I disagreed with JB through my emails they would discuss on the show, we always kept it civil. I used to get a chuckle about over how animated JB got by some of my questions. But he would always be gracious in our off the show e-mail exchanges. Then I heard how impressed he was by reading some of the posts in this forum. While I had plenty of disagreements with his positions, he did say that some of the talent he saw in this forum rivaled or exceeded what he experienced in the industry.

One of the weaknesses of the entire weather forecast industry right now is how much money they are spending on high tech approaches when several low tech approaches discussed in these threads are yielding better forecast results for a fraction of the cost. But the people running those big organizations get stuck in a very regimented way of thinking about how to recruit talent. They don’t realize how much money they are leaving on the table.