bluewave

Yeah, Dec 17-18 and Jan 21 were our only 30 day periods in 20s since 15-16. Minimum 30-Day Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 27.2 2018-01-19 0 23 29.3 2022-02-02 0

Yeah, all Western and Central troughs since the 15-16 super El Niño.

Yeah, at some point the warm spots like Newark should at least make the mid 80s this month. Could be a little higher like several years since 2010. Especially with the -PNA and SE Ridge. I will laugh if we still that have that Western Trough next winter again even with an El Niño. Would have to be a strong enough -PDO like the 72-73 El Niño to pull that one off.

Yeah, April 1976 was the only time the warmest day of the year was in April. But 2009 was a tie. Both years were followed by memorable winters. Monthly Highest Max Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2002 69 63 72 96 86 92 96 98 91 84 68 60 98 1976 56 70 72 96 83 92 90 94 89 73 61 55 96 2010 57 46 74 92 92 93 103 96 96 75 65 60 103 2009 47 65 70 92 86 84 86 92 84 74 69 66 92 1915 58 58 59 92 79 90 93 89 94 79 71 57 94 1990 66 65 85 91 83 89 95 93 89 84 78 66 95 1962 56 56 79 91 99 93 96 91 88 85 62 68 99 1942 57 52 69 91 92 89 97 93 93 84 74 58 97 1991 55 70 77 90 93 97 102 94 93 80 74 66 102

Looks like some more thunderstorms. But not the steep mid-level lapse rates and high helicity values like the other day. So no big tornado outbreak. But we may get enough instability and shear for some straight line severe gusts. We’ll see if Philly to CNJ is the thunderstorm magnet again. Maybe the stronger warm sector can help push some of the bigger storms closer to I-78 to I-80 this time.

The AMOC slowdown pulls the Gulf Stream in closer to the Northeast and only cools a small part of the North Atlantic south of Greenland. In the North Atlantic, the measured values differ markedly from the average global warming: the subpolar Atlantic (an area about half the size of the USA, south of Greenland) has hardly warmed up and in some cases even cooled down, contrary to the global warming trend. In contrast, a wide area along the American east coast has warmed up at an excessive rate. Both can be attributed to a weakening of the AMOC in the model simulation. The cooling is simply due to the reduced heat input from the AMOC. The excessive warming, on the other hand, is based on a somewhat more nerdy mechanism that has been known to experts for some time: if the AMOC weakens, the Gulf Stream shifts closer to the coast. (This has to do with conservation of angular momentum on the rotating globe.) study by Duchez et al. (2016) shows that cold in the North Atlantic correlates with summer heat in Europe. This is due to the fact that the heat transport in the Atlantic has not yet decreased strongly enough to cause cooling also over the adjacent land areas – but the cold of the sea surface is sufficient to influence the air pressure distribution. It does that in such a way that an influx of warm air from the south into Europe is encouraged. In summer 2015, the subpolar Atlantic was colder than ever since records began in the 19th century – associated with a heat wave in Europe. Haarsma et al (2015) argue on the basis of model calculations that the weakening of the AMOC will be the main cause of changes in the summer circulation of the atmosphere over Europe in the future. Jackson et al (2015) found that the slowdown could lead to increased storm activity in Central Europe. And a number of studies suggest that if the AMOC weakens, sea levels on the US coast will rise more sharply (e.g. Yin et al. 2009). The impacts are currently being further researched, but a further AMOC slowdown cannot be considered good news. Yet, although the oscillations seen in Fig. 2 suggest the AMOC may well swing up again for a while, a long-term further weakening is what we have to expect if we let global warming continue for much longer.

Yeah, Canada sticks out further to the East. So they can catch many recurving systems that miss the US.

I believe it comes down to the steering currents during the hurricane season. Bob was the last New England hurricane back in 1991. All the high impact events like Sandy had the eye come ashore south of 40N. From what I can see, the much warmer SSTs have allowed the subtropical ridge to push up into New England and Eastern Canada. So the high impact hurricanes have all come in further down the coast. Like the hurricanes have been squeezing under. The Gulf has been the main focus for most of the landfalling major hurricanes in the last 30 years. During the previous 40, it was more evenly divided between Gulf and East Coast. https://www.aoml.noaa.gov/hrd/hurdat/All_U.S._Hurricanes.html 1991 Aug RI, 2; MA, 2; NY, 2; CT, 2 2 962 90 Bob 1992 Aug FL, SE5, SW4; LA, 3 5 922 145 Andrew 1993 Aug * NC, 3 3 961 100 Emily 1994 None 1995 Aug FL, NW2, SE1 2 973 85 Erin 1995 Oct FL, NW3, I-AL 1 3 942 100 Opal 1996 Jul NC, 2 2 974 90 Bertha 1996 Sep NC, 3 3 954 100 Fran 1997 Jul LA, 1; AL, 1 1 984 70 Danny 1998 Aug NC, 2 2 964 95 Bonnie 1998 Sep FL, NW1 1 987 70 Earl 1998 Sep FL, SW2; MS, 2 2 964 90 Georges 1999 Aug TX, S3 3 951 100 Bret 1999 Sep NC, 2 2 956 90 Floyd 1999 Oct * FL, SW1; NC, 2 2 964 95 Irene 2000s 2000 None 2001 None 2002 Oct LA, 1 1 963 80 Lili 2003 Jul TX, C1 1 979 80 Claudette 2003 Sep NC, 2; VA, 1 2 957 90 Isabel 2004 Aug * NC, 1 1 972 70 Alex 2004 Aug FL, SW4, SE1, NE1; SC, 1; NC, 1 4 941 130 Charley 2004 Aug SC, 1 1 985 65 Gaston 2004 Sep FL, SE2, SW1 2 960 90 Frances 2004 Sep AL, 3; FL, NW3 3 946 105 Ivan 2004 Sep FL, SE3, SW1, NW1 3 950 105 Jeanne 2005 Jul LA, 1 1 991 65 Cindy 2005 Jul FL, NW3; I-AL 1 3 946 105 Dennis 2005 Aug FL, SE1, SW1; LA, 3; MS, 3; AL, 1 3 920 110 Katrina 2005 Sep * NC, 1 1 982 65 Ophelia 2005 Sep FL, SW1; LA, 3; TX, N2 3 937 100 Rita 2005 Oct FL, SW3; FL, SE2 3 950 105 Wilma 2006 None 2007 Sep TX, N1; LA, 1 1 985 80 Humberto 2008 Jul TX, S1 1 967 75 Dolly 2008 Sep LA, 2 2 954 90 Gustav 2008 Sep TX, N2; LA, 1 2 950 95 Ike 2009 None 2010s 2010 None 2011 Aug NC, 1 1 952 75 Irene 2012 Aug LA, 1 1 966 70 Isaac 2012 Oct * NY, 1 1 942 65 Sandy 2013 None 2014 Jul NC, 2 2 973 85 Arthur 2015 None 2016 Sep FL, NW1 1 981 70 Hermine 2016 Oct * FL, NE2; GA, 1; SC, 1; NC, 1 2 963 85 Matthew 2017 Aug TX,C4 4 937 115 Harvey 2017 Sep FL, SW4,SE 1 4 931 115 Irma 2017 Oct LA 1, MS 1 1 983 65 Nate 2018 Sep NC, 1 1 956 80 Florence 2018 Oct FL, NW5; I-GA, 2 5 919 140 Michael 2019 Jul LA, 1 1 993 65 Barry 2019 Sep NC, 2 2 956 85 Dorian 2020s 2020 Jul TX, S1 1 973 80 Hanna 2020 Aug NC, 1; SC, 1 1 986 80 Isaias 2020 Aug LA, 4; TX, N1 4 939 130 Laura 2020 Sep AL, 2; FL, NW2 2 965 95 Sally 2020 Oct LA,2 2 970 85 Delta 2020 Oct LA,3; MS, 2; I-AL, 1 3 970 100 Zeta 2021 Aug LA,4 4 931 130 Ida 2021 Sep TX,N1 1 991 65 Nicholas

Same goes for the PNA. We used to get much more negative values back in the 1950s to the 1970s. March was the deepest the trough got this year.

The GOA SSTs are mostly a function of Rossby waves being driven from the subtropical and tropical parts of the Pacific. So record SSTs to the south of that area are probably driving that process. Same goes for the increasing SE Ridge or WAR in our region. A 7° increase in the Gulf Stream off the Mid-Atlantic subtropics can cause an expansion of the subtropical ridge into our area. Notice how the models consistently underestimate the SE Ridge in the day 11-15 forecast. Also look back at winter forecasts for the US from all the private and public forecasters. The seasonal maps have underestimated the warmth in area. So we have to look into changes with the Gulf Stream we see a very anomalous 8 warmer than average winters in a row for the Northeast.

This tweet gives another answer to your good question.

The March -2.35 -PDO was the lowest in March since 1956 when the reading was -2.93. March 2009 was the last time below -2 in March at -2.06. Near record trough along the West Coast driving the SST pattern. So these are the warmest SSTs anomalies near the coast of South America in March for such a cold PDO. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

It’s a good observation. -PNA and +AO patterns of the 1950s and 1960s didn’t have the SE Ridge. So those patterns were colder and snowier than what we have been getting recently. The Gulf Stream is much warmer and pumps the SE Ridge.

This was the deepest trough from December to March over California since the 1970s. A bit of a departure from recent years with the record ridge that was in place. The years with the lowest heights are below. Got a stronger SE Ridge this year than composite. So the record warm pool over the the Gulf Stream helped boost the SE Ridge and displace the 50/50 low even with strong blocking intervals. 2023 5591 1998 5597 1979 5598 1975 5595 1973 5586 1969 5564 1949 5558

The 95-96 measurements were close to the surrounding areas. Data for October 1, 1995 through April 30, 1996 Click column heading to sort ascending, click again to sort descending. State Name Station Type Total Snowfall CT DANBURY COOP 118.4 NY YORKTOWN HEIGHTS 1W COOP 103.7 NY PORT JERVIS COOP 97.3 NJ CHARLOTTEBURG RESERVOIR COOP 96.0 NY WALDEN 1 ESE COOP 95.2 NY GARDNERVILLE COOP 92.3 NY PATCHOGUE 2 N COOP 92.0 NY WEST POINT COOP 90.7 CT JEWETT CITY COOP 90.0 NY WEST NYACK COOP 88.4 CT MIDDLETOWN 4 W COOP 85.0 NY BRIDGEHAMPTON COOP 84.0 NY DOBBS FERRY-ARDSLEY COOP 83.1 CT STAMFORD 5 N COOP 82.2 NY WESTCHESTER CO AP WBAN 80.7 NY GREENPORT POWER HOUSE COOP 80.0 NY RIVERHEAD RESEARCH FARM COOP 78.8 NJ NEWARK LIBERTY INTL AP WBAN 78.4 NY LAGUARDIA AIRPORT WBAN 77.9 NY MINEOLA 1 NE COOP 77.8 NY ISLIP-LI MACARTHUR AP WBAN 77.1 CT COCKAPONSET RANGER STA COOP 76.0 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 75.7 NY NY CITY CENTRAL PARK WBAN 75.6 CT NORWICH PUBLIC UTILITY PLANT COOP 74.3 NY SUFFERN COOP 73.9 NJ GREENWOOD LAKE COOP 73.1 NJ PLAINFIELD COOP 71.4 CT GROTON COOP 71.4 NY NEW YORK AVE V BROOKLYN COOP 69.9 NJ TETERBORO AIRPORT WBAN 69.5 NY OCEANSIDE COOP 69.0 NY JFK INTERNATIONAL AIRPORT WBAN 69.0 NJ WANAQUE RAYMOND DAM COOP 66.6 NJ MIDLAND PARK COOP 66.3 NJ CANOE BROOK COOP 65.5

Very volatile snowfall seasons since the 1990s. There were 6 top 10 snowiest and 8 least snowiest years. So doing seasonal snowfall forecasting has been nearly impossible. Very big swings between years. Much less variation in the 60s, 70s, and 80s. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1996-04-30 69.0 0 2 1961-04-30 58.5 0 3 2003-04-30 56.2 0 4 1978-04-30 48.5 0 5 2010-04-30 47.2 0 6 1967-04-30 47.0 0 7 2014-04-30 45.6 0 8 1994-04-30 45.2 0 9 2015-04-30 44.2 0 10 2011-04-30 42.0 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1973-04-30 1.6 0 2 2023-04-30 2.1 29 3 1998-04-30 3.6 0 4 2012-04-30 3.7 0 5 2020-04-30 3.8 0 6 2002-04-30 4.5 0 7 1995-04-30 7.9 0 8 1989-04-30 8.2 0 9 2007-04-30 8.5 0 10 1990-04-30 9.6 0

Would be only the 7th April tornado in NJ. https://climate.rutgers.edu/stateclim/climatologies/njtornado.html We don’t know enough about this one yet for any analogs.

Yeah, we haven’t had 2 consecutive years under 5” before. Getting 0 is a challenge since even Philly, DC ,and Richmond haven’t been able to avoid a trace. Time Series Summary for NY CITY CENTRAL PARK, NY - Oct through Sep Click column heading to sort ascending, click again to sort descending. Rank Season Total Snowfall Missing Count 1 2022-2023 2.3 182 2 1972-1973 2.8 0 3 2001-2002 3.5 0 4 1918-1919 3.8 1 5 2019-2020 4.8 0 6 1900-1901 5.1 2 7 1931-1932 5.3 0 8 1997-1998 5.5 0 9 2011-2012 7.4 0 10 1988-1989 8.1 0 - 1877-1878 8.1 0 11 1950-1951 9.3 0 12 1996-1997 10.0 0 Time Series Summary for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1973-04-30 T 0 2 2023-04-30 0.3 29 - 2020-04-30 0.3 0 3 1998-04-30 0.8 0 4 1950-04-30 2.0 0 5 2012-04-30 4.0 0 - 2002-04-30 4.0 0 6 1931-04-30 4.1 0 7 1951-04-30 4.6 0 8 1992-04-30 4.7 0 9 1959-04-30 5.1 0 - 1942-04-30 5.1 0 10 1919-04-30 5.5 0 Time Series Summary for Washington Area, DC (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 1998-04-30 0.1 0 - 1973-04-30 0.1 0 3 2023-04-30 0.4 29 4 2020-04-30 0.6 0 5 2012-04-30 2.0 0 6 1976-04-30 2.2 0 7 1931-04-30 2.5 0 8 2013-04-30 3.1 0 9 2002-04-30 3.2 0 10 1919-04-30 3.3 0 Time Series Summary for Richmond Area, VA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1 2023-04-30 T 29 - 1919-04-30 T 0 2 1945-04-30 0.5 0 3 1951-04-30 0.7 0 4 2008-04-30 0.8 0 5 1992-04-30 0.9 0 6 1981-04-30 1.0 0 - 1921-04-30 1.0 1 7 1956-04-30 1.1 0 8 1998-04-30 1.2 88 - 1976-04-30 1.2 0 9 2007-04-30 1.3 0 10 2020-04-30 1.5 0

Warmth could be a factor again if this is another strong to super basin-wide event as outlined in the paper below. They theorize the expanding WPAC warm pool has lead to stronger El Niño’s since the 1970s. We only had 3 notably colder Modoki El Niño’s with 50”+ around NYC since the 1980s in 02-03, 09-10, and 14-15. Most other El Niño’s were near average to above normal warmth in 82-83, 86-87, 87-88, 91-92, 94-95, 97-98, 04-05, 06-07 and 15-16. So 3 out of 12 notably colder with 50”+ snow. So that was the rarest group. Snowfall was much more variable among the remaining 9 years. 2 super El Niño years had memorable snowstorms in 82-83 and 15-16 in warm winters. The 97-98 super was a disappointment with all warmth an little snow. 86-87 and 04-05 El Niño’s had decent snows around the region with near normal temperatures. Odd years like 06-07 and 94-95 were milder without much snow. https://www.pnas.org/doi/10.1073/pnas.1911130116 Historical change of El Niño properties sheds light on future changes of extreme El Niño 49,207114 Significance How the magnitude of El Niño will change is of great societal concern, yet it remains largely unknown. Here we show analysis of how changing El Niño properties, due to 20th century climate change, can shed light on changes to the intensity of El Niño in the future. Since the 1970s, El Niño has changed its origination from the eastern Pacific to the western Pacific, along with increased strong El Niño events due to a background warming in the western Pacific warm pool. This suggests the controlling factors that may lead to increased extreme El Niño events in the future. If the observed background changes continue under future anthropogenic forcing, more frequent extreme El Niño events will induce profound socioeconomic consequences. Abstract El Niño’s intensity change under anthropogenic warming is of great importance to society, yet current climate models’ projections remain largely uncertain. The current classification of El Niño does not distinguish the strong from the moderate El Niño events, making it difficult to project future change of El Niño’s intensity. Here we classify 33 El Niño events from 1901 to 2017 by cluster analysis of the onset and amplification processes, and the resultant 4 types of El Niño distinguish the strong from the moderate events and the onset from successive events. The 3 categories of El Niño onset exhibit distinct development mechanisms. We find El Niño onset regime has changed from eastern Pacific origin to western Pacific origin with more frequent occurrence of extreme events since the 1970s. This regime change is hypothesized to arise from a background warming in the western Pacific and the associated increased zonal and vertical sea-surface temperature (SST) gradients in the equatorial central Pacific, which reveals a controlling factor that could lead to increased extreme El Niño events in the future. The Coupled Model Intercomparison Project phase 5 (CMIP5) models’ projections demonstrate that both the frequency and intensity of the strong El Niño events will increase significantly if the projected central Pacific zonal SST gradients become enhanced. If the currently observed background changes continue under future anthropogenic forcing, more frequent strong El Niño events are anticipated. The models’ uncertainty in the projected equatorial zonal SST gradients, however, remains a major roadblock for faithful prediction of El Niño’s future changes.

The developing El Niño will become more basin wide instead of east based with the further west WWB than the more EPAC one in a March which warmed 1+2.

71 mph gust in Central NJ which has been an active area for severe in recent years.

That’s for sure.

Yeah, this SST profile keeps pumping the SE Ridge.

80 mph gust from Lake Erie buoy.