bluewave

If they measured the temperatures in Central Park the same way they did before the 1990s, then NYC would average closer to 29 days a year reaching 90° than the 19 days since the warmer summer era began in 2010. 1951-1980 average number of 90° days EWR….23 NYC….18 LGA…..15 2010-2023 warmer era EWR….33 NYC…..19…actual ..close to 29 LGA…..26

Taking the Central Park temperatures under the trees since the new ASOS was installed back in the 90s created an artificial cooling of daytime highs during the the warm season. When they measured the temperatures away from the trees prior to the 1990s, NYC had more 90° days than LGA. So the decline in 90° days from 30 years before and after the new ASOS was installed is an artifact of the poor sitting and not a reflection of the actual temperatures in Central Park which used to be warmer than LGA. All our other stations away from the sea breeze have seen a steep increase in 90° days over this period. https://www.nytimes.com/1977/07/22/archives/vandals-in-central-park-forcing-weather-service-to-seek-new-site.html When the devices at the castle are not functioning, the Weather Service substitutes readings from La Guardia Airport. But Mr. Gibson said those readings do not really reflect conditions in the city, because they may be several degrees cooler in summer or warmer in winter than those in Central Park. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=74&network=NJCLIMATE&station=NJTNBR&season=all&dir=above&var=high&threshold=90&year=1960&_r=t&dpi=100&_fmt=png

We came close back in 2022. But notice all the 40 day years recently reaching 90°. 2011 and 2012 had a much lower number of 90° days. But noteworthy shorter record heatwaves centered in July. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 90 Missing Count 1 2010 54 0 2 2022 49 0 - 1993 49 0 3 1988 43 0 4 2021 41 0 - 2002 41 0 - 1991 41 0 5 2016 40 0 - 1983 40 0 - 1959 40 0 6 1994 39 0 - 1944 39 0 7 2005 37 0 - 1987 37 0 8 2018 36 0 - 1949 36 0 9 2015 35 0 10 1961 34 0 11 2012 33 0 - 1999 33 0 - 1995 33 0 - 1966 33 0 12 1955 32 0 - 1953 32 0 - 1943 32 0 13 2020 31 0 - 2011 31 0 - 1973 31 0 - 1952 31 0

2010 is the only summer that the coastal stations stations haven’t been able to beat. The summers after 2011 did have the memorable 105-108° maxes. But the heat peaked during 30 day periods centered around July. Our recent summers have had extended warmth throughout the summer. Places like Newark have already surpassed 2010 in the last few years. The lack of westerly flow in recent years has favored the stations away from the shore for the most extreme heat. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2010 74.7 0 2 2022 74.6 0 - 2020 74.6 0 3 1999 74.5 0 4 2016 74.4 0 5 2011 73.9 0 6 2019 73.8 0 7 2021 73.7 0 8 2018 73.5 0 - 2005 73.5 0 9 2013 73.4 0 10 2012 73.3 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2022 79.2 0 - 1993 79.2 0 2 2010 78.7 0 3 1994 78.5 0 4 2021 78.3 0 5 2011 78.0 0 6 2005 77.8 0 7 1988 77.7 0 8 2020 77.6 0 - 2016 77.6 0 - 1973 77.6 0 9 1999 77.1 0 10 1995 77.0 0

Yeah, the El Niño releases the excess heat building up in the oceans as the climate warms. So the El Niño itself isn’t causing the warming. If we had a stable climate like in the late 1800s, the global temperatures would quickly drop in few years like after the super El Niño like in 1877-1878. But as the climate continues to warm, each El Niño year sees a new annual jump. So it’s mostly a modulator of which years set new global temperature records between the neutral or La Nina years. I guess we have been lucky that the pace of the summer warming since 2010 hasn’t been as high as the winter warming since 2015.

Each new El Niño boosts the temperatures to a higher baseline. The 09-10 El Niño marked the beginning of a much warmer summer pattern which continues to this day. The 15-16 El Niño coincided with a shift to much warmer winters. The winter warming shift was of a higher magnitude than we have seen relative to the previous means than the summers. Now the global temperature jump with the 23-24 El Niño was even higher than the 15-16 super El Niño even though it wasn’t as strong. So it will be interesting to see what happens to our temperatures and weather patterns in coming years at this even higher temperature baseline.

It was good to see how much we were able to dry out this month. Monthly Total Precipitation for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Season 2023-2024 6.71 5.28 1.35 13.34

Very amplified -PNA Southeast ridge pattern coming up. The amount of rain will depend on whether something tries to cutoff underneath. If we can escape the cutoffs, then just the typical cuttters with showers and maybe some thunderstorms from time to time.

You know how it goes. Low 60s if there are showers and clouds. But any breaks of sun mid 60s or possibly higher for the warm spots away from the shore. Hopefully the Euro is correct and we get more sun with a slower frontal passage.

Early start to spring this week.

That’s for sure. Another case of the warm minimums driving the departures. Pretty wild to see Upstate NY with low temperature departures for the whole winter in the +7 +11 range above the much warmer 91-20 climate normals.

No surprise all the guidance has gone warm when we see a 6 sigma jet max over the North Pacific.

Continuation of the all or nothing snowfall theme at Islip since 1994. Nearly all the seasons have been under 15” or over 30”. Before 1994 we had numerous seasons in the over 15” and under 30 range So the winter warming has introduced a higher degree of volatility into the snowfall patterns. Eventually the under 15” seasons will begin to dominate as it continues to warm. But hopefully we can get more of the over 30” seasons before it just becomes to warm for above average snowfall seasons. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 2024-04-30 10.9 67 2023-04-30 5.0 0 2022-04-30 37.0 0 2021-04-30 33.5 0 2020-04-30 6.8 0 2019-04-30 12.8 0 2018-04-30 65.9 0 2017-04-30 39.3 0 2016-04-30 41.4 0 2015-04-30 63.7 0 2014-04-30 63.7 0 2013-04-30 46.9 0 2012-04-30 4.7 0 2011-04-30 55.3 0 2010-04-30 53.8 0 2009-04-30 36.2 0 2008-04-30 10.7 0 2007-04-30 9.0 0 2006-04-30 36.0 0 2005-04-30 58.8 0 2004-04-30 41.4 0 2003-04-30 54.6 0 2002-04-30 3.7 1 2001-04-30 38.9 1 2000-04-30 9.0 0 1999-04-30 19.4 0 1998-04-30 2.6 0 1997-04-30 12.4 1 1996-04-30 77.1 0 1995-04-30 5.1 0 1994-04-30 37.1 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1993-04-30 28.6 0 1992-04-30 13.4 0 1991-04-30 13.8 0 1990-04-30 19.0 0 1989-04-30 19.0 0 1988-04-30 19.5 0 1987-04-30 22.5 0 1986-04-30 15.2 0 1985-04-30 26.9 0 1984-04-30 27.5 0 1983-04-30 31.9 0 1982-04-30 35.4 0 1981-04-30 20.8 0 1980-04-30 9.0 0 1979-04-30 28.1 0 1978-04-30 68.0 0 1977-04-30 28.0 0 1976-04-30 30.2 0 1975-04-30 14.5 0 1974-04-30 34.0 0 1973-04-30 4.5 0 1972-04-30 15.6 0 1971-04-30 18.9 0 1970-04-30 27.0 0 1969-04-30 33.5 0 1968-04-30 22.6 0 1967-04-30 50.8 0 1966-04-30 15.7 0 1965-04-30 39.5 0 1964-04-30 39.7 6

Officially the lowest 2 year average snowfall at only 7” for LGA.

Yeah, we had an neutral to slightly -EPO in Jan 22. But it wasn’t the wall to wall stronger -EPO for much of the winter like in 13-14 and 14-15. It’s been very tough to get extended winter -EPOs beyond a few weeks to a month since then. The EPS has had issues showing too much -EPO beyond 10 to 15 days only to correct weaker the closer in we get. The coming week was originally forecast to be a strong -EPO -NAO pattern. The model has been doing this all winter in the 3rd and 4th weeks.

Yeah, 13-14 and 14-15 were the last time we had a strong -EPO pattern during the winter.

We had a great -EPO pattern in mid-March 1998.

The 97-98 season was one of the few times that March had a colder daily departure in NYC than during DJF. The -16 on the 12th was the coldest of the entire season. So we needed that colder period in mid-March to prime the pattern for snow on the 22nd. NYC had two days with highs not getting above freezing after March 10th which is rare by todays standards.

We needed that Arctic outbreak about 10 days before the 3-22 snowstorm in NYC. The record 80s warmth didn’t occur until after the snow in March 1998.

Bradford was actually warmer than the winter of 01-02 for 2 years in a row now. Time Series Summary for BRADFORD REGIONAL AIRPORT, PA - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2023-2024 32.7 7 2 2022-2023 32.0 0 3 2001-2002 30.9 0 4 1997-1998 30.2 8 5 2016-2017 29.3 0 - 2015-2016 29.3 0 6 2011-2012 29.2 0 7 2012-2013 28.9 0 8 2019-2020 28.8 0 9 2021-2022 27.4 1 10 1998-1999 27.3 0

Good question. Plus we may be dealing with non-linear changes involving threshold temperatures for deep convection. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101499

We have had a Virginia winter temperature regime in place since the +13.3 December 2015. NYC has been at a new winter average of 38.5° lasting almost an entire decade. The previous 1981-2010 winter average was 35.1° So that is +3.4 warmer over a 9 winter period. Plus this is a regional event for the East and many other sites have made a shift like this in December 2015 and are at +3 to +4 over 1981-2010 climate normals. I am not aware of any other region of the country that has ever had nearly a decade at +3.4° above the previous 30 year climate normals. It’s seems like the frequent marine heatwaves in the Eastern IO to WPAC have loaded the dice for more forcing in these regions which is warm for us. I don’t really know what it would take to shift this pattern. Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Feb Season Mean 41.0 35.7 38.8 38.5 2023-2024 44.6 37.0 39.4 40.4 2022-2023 38.5 43.5 41.1 41.0 2021-2022 43.8 30.3 37.3 37.1 2020-2021 39.2 34.8 34.2 36.1 2019-2020 38.3 39.1 40.1 39.2 2018-2019 40.1 32.5 36.2 36.3 2017-2018 35.0 31.7 42.0 36.1 2016-2017 38.3 38.0 41.6 39.3 2015-2016 50.8 34.5 37.7 41.0

Looks like this will end up as a 10-15.6” winter for most closer to the coast. CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 15.6 CT RIDGEFIELD 3.6 N CoCoRaHS 15.6 CT GUILFORD COOP 15.5 CT MIDDLEFIELD 1.4 W CoCoRaHS 15.5 CT DANBURY COOP 15.4 NY MOUNT SINAI COOP 15.3 NJ GLEN ROCK 0.7 SSE CoCoRaHS 15.2 NY HOWARD BEACH 0.4 NNW CoCoRaHS 15.2 NJ WAYNE TWP 0.8 SSW CoCoRaHS 14.9 CT NORWALK 2.9 NNW CoCoRaHS 14.7 CT NEW CANAAN 3.8 N CoCoRaHS 14.7 NJ NEW PROVIDENCE 0.8 ESE CoCoRaHS 14.7 NY RIDGE 1.5 SE CoCoRaHS 14.5 NJ CLARK TWP 1.3 ENE CoCoRaHS 14.3 NJ POMPTON LAKES 1.0 ENE CoCoRaHS 14.2 NY COMMACK 1.3 SW CoCoRaHS 14.1 NY PORT JEFFERSON STATION 0.3 SSW CoCoRaHS 13.9 CT NORWICH 5.4 SE CoCoRaHS 13.9 NY NESCONSET 1.4 SSW CoCoRaHS 13.7 NJ TENAFLY 1.3 W CoCoRaHS 13.6 NJ MONTCLAIR 0.7 N CoCoRaHS 13.5 CT HIGGANUM 0.8 NE CoCoRaHS 13.5 NJ HAWTHORNE 1.0 SSE CoCoRaHS 13.4 NY NEW HEMPSTEAD 0.6 SE CoCoRaHS 13.4 CT RIDGEFIELD 3.7 NNE CoCoRaHS 13.4 NY STATEN ISLAND 1.4 SE CoCoRaHS 13.4 NJ VERONA TWP 0.8 W CoCoRaHS 13.3 NJ FAIR LAWN 1.2 SE CoCoRaHS 13.2 NY BRIGHTWATERS 0.7 NNW CoCoRaHS 13.1 NY ST. JAMES COOP 13.0 NY JFK INTERNATIONAL AIRPORT WBAN 12.8 NY UPTON COOP - NWSFO NEW YORK COOP 12.7 NY MANHASSET HILLS 0.2 NNE CoCoRaHS 12.4 NJ HARRISON COOP 12.4 CT MYSTIC 3.4 NW CoCoRaHS 12.4 CT SEYMOUR 1.2 WSW CoCoRaHS 12.4 CT NORWICH 5.2 SE CoCoRaHS 12.3 NJ NEWARK LIBERTY INTL AP WBAN 12.2 CT KILLINGWORTH 2.6 ESE CoCoRaHS 12.2 NJ KEARNY 1.7 NNW CoCoRaHS 11.6 NJ MAPLEWOOD TWP 0.9 SE CoCoRaHS 11.2 CT NORWICH PUBLIC UTILITY PLANT COOP 11.1 NJ RIVER EDGE 0.4 NNE CoCoRaHS 11.0 CT ANSONIA 1 NE COOP 11.0 NY BELLMORE 0.9 SSE CoCoRaHS 10.9 NY ISLIP-LI MACARTHUR AP WBAN 10.9 CT STRATFORD 0.9 W CoCoRaHS 10.9 NY SYOSSET COOP 10.8 CT BETHEL 4.5 SSE CoCoRaHS 10.8 NY LITTLE NECK 0.3 SE CoCoRaHS 10.7 NY RIVERHEAD RESEARCH FARM COOP 10.7 NY LAGUARDIA AIRPORT WBAN 10.5 CT PAWCATUCK 1.8 SSE CoCoRaHS 10.3 NY WEST POINT COOP 10.2 NJ WEST CALDWELL TWP 1.3 NE CoCoRaHS 10.2 NJ WESTFIELD 0.8 WSW CoCoRaHS 10.2 CT WALLINGFORD CENTER 1.9 WNW CoCoRaHS 10.1 NY AMITYVILLE 0.6 NNE CoCoRaHS 10.0 NY REMSENBURG-SPEONK 0.9 NE CoCoRaHS 10.0

No surprise we are seeing this big warm up as these are some off the warmest SSTs ever recorded this time of year near the Maritime Continent driving the forcing there.