bluewave

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.

Pretty impressive for UCLA to establish the new all-time monthly rainfall record beating the 1998 El Niño.

The Pacific has been much more important for us than than anything happening with the stratosphere or the -NAO. Next week we’ll see our strongest -PNA trough since last spring. So it looks like a warm pattern for us from late February into early March. If a more -NAO pattern develops by mid-March, then it will come down to the Pacific again. If that -PNA trough dominates, then it will be warm like last March was with the -PNA -NAO.

This El Niño is finally fading as the models have the strongest -PNA drop since last spring. If the clouds end up dominating next week, then the highs will only max out in upper 50s to low 60s. But a slower frontal passage and more breaks of sun will allow the warm spots to make a run on 70°.

These more south based blocks could be related to the record Atlantic SSTs.

It think it may be related to these more frequent south based blocks in recent years not having the same staying power as the older ones which where located closer to the Arctic.

That was the only time NYC had a 5” snowstorm so close to a string of 80° days. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Snowfall 1998-03-22 36 30 5.0 1998-03-23 47 32 0.0 1998-03-24 49 34 0.0 1998-03-25 50 34 0.0 1998-03-26 67 40 0.0 1998-03-27 83 56 0.0 1998-03-28 80 63 0.0 1998-03-29 81 62 0.0 1998-03-30 82 59 0.0 1998-03-31 86 66 0.0

Pretty impressive for Bradford,PA to beat the 01-02 winter warmth for two years in a row as the warmest departures missed just to our west. 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 32.6 9 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 Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 2001-2002 41.6 0 2 2022-2023 41.0 0 - 2015-2016 41.0 0 3 2023-2024 40.5 9 - 2011-2012 40.5 0 4 1931-1932 40.2 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 - 1889-1890 38.5 0

But the interior has been favored during recent Marches.

The MOS gets down to 19° but may be able to get closer to 17° again if the winds go calm faster.