bluewave

Extremely steep lapse rates and some CAPE should allow for gusts over 40 and small hail with the convection later today.

In general, the 2023 temperature anomaly has come out of the blue, revealing an unprecedented knowledge gap perhaps for the first time since about 40 years ago, when satellite data began offering modellers an unparalleled, real-time view of Earth’s climate system. If the anomaly does not stabilize by August — a reasonable expectation based on previous El Niño events — then the world will be in uncharted territory. It could imply that a warming planet is already fundamentally altering how the climate system operates, much sooner than scientists had anticipated. It could also mean that statistical inferences based on past events are less reliable than we thought, adding more uncertainty to seasonal predictions of droughts and rainfall patterns. Much of the world’s climate is driven by intricate, long-distance links — known as teleconnections — fuelled by sea and atmospheric currents. If their behaviour is in flux or markedly diverging from previous observations, we need to know about such changes in real time. We need answers for why 2023 turned out to be the warmest year in possibly the past 100,000 years. And we need them quickly. Nature 627, 467 (2024) doi: https://doi.org/10.1038/d41586-024-00816-z

The 1980s and 1990s were no comparison to the warmth and lack of snow during the 2020s so far. I will use LGA stats to compare since NYC has been consistently undermeasuring snowfall. While we are only half way through the 2020s, we would need a significant cool down and snowfall increase next 5 years to avoid the warmest and least snowiest decade on record. If global and local temperatures continue rising at the same rate, then we will eventually have a whole decade with the average snowfall under 10” and the average winter temperature over 40.0°. LGA 2020s so far snowfall average….15.8”….DJF ave temp…39.2° ………1990s………..27.1”………………………….36.7° ………1980s………..21.0”…………………………34.5°

Yeah, it would be interesting to see specifically which aspect of the warming in the system lead to this outcome. Notice the extreme volatility of the AO between positive and negative. Maybe the IO to WPAC MJO driven Rossby wave train competing with the El Niño was interfering with the coupling. So every drop of the -AO was answered by and quick increase.

Yeah, beach erosion and coastal flooding have become the new normal with the more extreme storms and rising sea levels.

Much more model spread than we typically see around 5 days out. The potential for heavy rains is there if everything gels. But this is a lower confidence forecast than usual since cutoffs in spring are the hardest for models to resolve. Each model has a different low position at 120 hrs.

They did much better last March with the -NAO and record MJO 8.

Gorgeous photos of the roll clouds on the South Shore yesterday. https://www.facebook.com/permalink.php?story_fbid=pfbid0ehVZDaAGaxnLjfGngNWK82TSG5WHZYNaYbRUhBtJ3u6WtsFnrfUuyyhYjH31z153l&id=100000492031103

It’s the areas that sustain a hard freeze in the mid 20s that are most susceptible to plant damage after an early bloom. https://hortnews.extension.iastate.edu/faq/hard-freeze-early-spring-damaged-newly-emerged-growth-several-trees-and-shrubs-will-plants Question: A hard freeze in early spring damaged the newly emerged growth on several trees and shrubs. Will the plants recover? Answer: Newly emerged tree and shrub foliage is susceptible to damage from below freezing temperatures. The new growth on many trees and shrubs can tolerate temperatures in the low 30s and upper 20s. Freeze damage is most likely when temperatures drop into the middle 20s or below. Symptoms of freeze damage include shriveling and browning or blackening of damaged tissue. Damaged growth usually becomes limp. Eventually, damaged or destroyed leaves drop from the tree or shrub. Fortunately, trees and shrubs have the ability to leaf out again if the initial growth is damaged or destroyed. Damaged trees and shrubs have only suffered a temporary setback. Healthy, well established trees and shrubs will produce additional growth within a few weeks. Good care during the remainder of the year, such as watering during dry periods, should aid the recovery of trees and shrubs planted within the past two or three years.

The Seattle forecast zones actually got to 80° before our area this March.

Yeah, March was more like a winter month during the 2010s and now it’s a spring month in the 2020s. So it’s a challenge reaching normal seasonal snowfall when we don’t get much snow these days in December and March since they have become so warm. Very hard to get to normal when you are just relying on January and February. Plus the warmth has been encroaching on those months also reducing snowfall potential. So a continuation of our climate becoming more like what areas to our south in the Mid-Atlantic used to be like in the old days.

NYC will need to see some snowfall improvement the next 5 years for the 2020s to avoid being the lowest snowfall decade following the highest during the 2010s since 1950. 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 T 2.6 4.4 7.1 0.1 T 14.2 2023-2024 0.0 T T 2.3 5.2 T M 7.5 2022-2023 0.0 0.0 T T 2.2 0.1 0.0 2.3 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 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 0.3 1.1 5.3 12.9 11.8 6.0 0.6 37.9 2018-2019 0.0 6.4 T 1.1 2.6 10.4 0.0 20.5 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 2011-2012 2.9 0.0 0.0 4.3 0.2 0.0 0.0 7.4 2010-2011 0.0 T 20.1 36.0 4.8 1.0 T 61.9 2009-2010 0.0 0.0 12.4 2.1 36.9 T 0.0 51.4 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 T T 6.6 7.2 10.1 3.5 0.5 28.0 2008-2009 0.0 T 6.0 9.0 4.3 8.3 T 27.6 2007-2008 0.0 T 2.9 T 9.0 T 0.0 11.9 2006-2007 0.0 0.0 0.0 2.6 3.8 6.0 T 12.4 2005-2006 0.0 T 9.7 2.0 26.9 1.3 0.1 40.0 2004-2005 0.0 T 3.0 15.3 15.8 6.9 0.0 41.0 2003-2004 0.0 0.0 19.8 17.3 0.7 4.8 0.0 42.6 2002-2003 T T 11.0 4.7 26.1 3.5 4.0 49.3 2001-2002 0.0 0.0 T 3.5 T T T 3.5 2000-2001 T 0.0 13.4 8.3 9.5 3.8 0.0 35.0 1999-2000 0.0 0.0 T 9.5 5.2 0.4 1.2 16.3 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 3.0 6.1 8.7 5.7 0.1 24.4 1998-1999 0.0 0.0 2.0 4.5 1.7 4.5 0.0 12.7 1997-1998 0.0 T T 0.5 0.0 5.0 0.0 5.5 1996-1997 0.0 0.1 T 4.4 3.8 1.7 T 10.0 1995-1996 0.0 2.9 11.5 26.1 21.2 13.2 0.7 75.6 1994-1995 0.0 T T 0.2 11.6 T T 11.8 1993-1994 0.0 T 6.9 12.0 26.4 8.1 0.0 53.4 1992-1993 0.0 0.0 0.4 1.5 10.7 11.9 0.0 24.5 1991-1992 0.0 T 0.7 1.5 1.0 9.4 T 12.6 1990-1991 0.0 0.0 7.2 8.4 9.1 0.2 0.0 24.9 1989-1990 0.0 4.7 1.4 1.8 1.8 3.1 0.6 13.4 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 T 0.1 2.3 7.9 5.4 3.0 1.0 19.7 1988-1989 0.0 0.0 0.3 5.0 0.3 2.5 0.0 8.1 1987-1988 0.0 1.1 2.6 13.9 1.5 T 0.0 19.1 1986-1987 0.0 T 0.6 13.6 7.0 1.9 0.0 23.1 1985-1986 0.0 T 0.9 2.2 9.9 T T 13.0 1984-1985 0.0 T 5.5 8.4 10.0 0.2 T 24.1 1983-1984 0.0 T 1.6 11.7 0.2 11.9 0.0 25.4 1982-1983 0.0 0.0 3.0 1.9 21.5 T 0.8 27.2 1981-1982 0.0 0.0 2.1 11.8 0.4 0.7 9.6 24.6 1980-1981 0.0 T 2.8 8.0 T 8.6 0.0 19.4 1979-1980 T 0.0 3.5 2.0 2.7 4.6 T 12.8 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 T 0.3 2.0 8.0 9.9 2.3 0.1 22.5 1978-1979 0.0 2.2 0.5 6.6 20.1 T T 29.4 1977-1978 0.0 0.2 0.4 20.3 23.0 6.8 T 50.7 1976-1977 0.0 T 5.1 13.0 5.8 0.6 T 24.5 1975-1976 0.0 T 2.3 5.6 5.0 4.4 T 17.3 1974-1975 0.0 0.1 0.1 2.0 10.6 0.3 T 13.1 1973-1974 0.0 0.0 2.8 7.8 9.4 3.2 0.3 23.5 1972-1973 T T T 1.8 0.8 0.2 T 2.8 1971-1972 0.0 T T 2.8 17.8 2.3 T 22.9 1970-1971 0.0 0.0 2.4 11.4 T 1.3 0.4 15.5 1969-1970 0.0 T 6.8 8.4 6.4 4.0 T 25.6 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 T 0.4 8.3 7.1 10.1 6.1 0.1 32.0 1968-1969 0.0 T 7.0 1.0 16.6 5.6 0.0 30.2 1967-1968 0.0 3.2 5.5 3.6 1.1 6.1 0.0 19.5 1966-1967 0.0 0.0 9.1 1.4 23.6 17.4 T 51.5 1965-1966 T 0.0 T 11.6 9.8 T 0.0 21.4 1964-1965 0.0 0.0 3.1 14.8 2.5 2.8 1.2 24.4 1963-1964 0.0 T 11.3 13.3 14.1 6.0 T 44.7 1962-1963 T T 4.5 5.3 3.7 2.8 T 16.3 1961-1962 0.0 T 7.7 0.6 9.6 0.2 T 18.1 1960-1961 T 0.0 18.6 16.7 18.2 1.2 T 54.7 1959-1960 0.0 0.5 15.8 2.5 1.9 18.5 0.0 39.2 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 0.1 0.5 3.3 4.8 4.0 6.2 1.0 19.9 1958-1959 0.0 T 3.8 1.5 0.4 6.7 0.6 13.0 1957-1958 0.0 T 8.7 9.2 10.7 15.9 0.2 44.7 1956-1957 0.0 T 0.9 8.9 7.0 2.6 2.5 21.9 1955-1956 0.0 1.0 3.3 1.2 2.7 21.1 4.2 33.5 1954-1955 0.0 T 0.1 2.6 5.2 3.6 0.0 11.5 1953-1954 0.0 2.2 T 12.7 0.5 0.1 0.3 15.8 1952-1953 0.5 1.7 7.5 4.1 0.4 0.9 T 15.1 1951-1952 0.0 T 3.3 6.2 2.8 7.4 0.0 19.7 1950-1951 0.0 T 3.8 0.9 1.9 2.7 0.0 9.3 1949-1950 0.0 0.5 1.3 0.4 8.5 1.4 1.9 14.0

March was more like a winter month during the 2010s and is now a spring month In the 2020s. Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Mar Season Mean 46.5 46.5 2024 48.7 48.7 2023 44.6 44.6 2022 45.3 45.3 2021 45.8 45.8 2020 48.0 48.0 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Mar Season Mean 0.1 0.1 2024 T T 2023 0.1 0.1 2022 0.4 0.4 2021 T T 2020 T T Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Mar Season Mean 42.7 42.7 2019 41.7 41.7 2018 40.1 40.1 2017 39.2 39.2 2016 48.9 48.9 2015 38.1 38.1 2014 37.7 37.7 2013 40.1 40.1 2012 50.9 50.9 2011 42.3 42.3 2010 48.2 48.2 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Mar Season Mean 6.0 6.0 2019 10.4 10.4 2018 11.6 11.6 2017 9.7 9.7 2016 0.9 0.9 2015 18.6 18.6 2014 0.1 0.1 2013 7.3 7.3 2012 0.0 0.0 2011 1.0 1.0 2010 T T

Looks like mid-70s for the warm spots in NJ west of the sea breeze today.

NYC only needs another 2.00” of rain for a top 10 wettest March. So a rainy period later in the month can push NYC into the top 10.

Looks like only scattered showers with the frontal passages over the next week or so. This will translate into below average rainfall with no very heavy rainfalls of several inches expected. Then we shift back to a wetter pattern later in the month as it’s been tough to sustain any drier intervals since last summer.

3 of the top 5 warmest first 2 weeks of March have occurred since the 15-16 super El Niño. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Mar 1 to Mar 14 Missing Count 1 2020-03-14 49.0 0 2 1977-03-14 48.5 0 3 2024-03-14 48.2 2 4 2016-03-14 47.9 0 5 2012-03-14 47.6 0

Too bad the phase wasn’t a little further southeast allowing a benchmark track instead.

UHI isn’t a factor for record cold like that since NYC has needed strong CAA back to around 1900 when UHI became established. It’s that the air masses aren’t as cold anymore as they were as recently as the late 70s to early 90s. Newark had one of their coldest readings of all time as recently as the 1980s while UHI was well established. NYC has always needed northerly flow for the few times it got below -10°. UHI mostly means that on nights with calm winds and clear skies the surrounding areas will radiate much better. But the best Arctic outbreaks in NYC always need strong winds to transport the Arctic air from the north and west. That’s why there isn’t that much difference between NYC and nearby less urban stations when the winds stay strong. It’s on the nights when the winds are calm that we see the big disparity. 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 Lowest Min Temperature Missing Count 1 1934 -14 0 2 1985 -8 0 - 1933 -8 0 3 1982 -7 0 - 1943 -7 0 4 1936 -4 0 - 1935 -4 0 5 1994 -2 0 - 1977 -2 0 - 1963 -2 0 - 1961 -2 0 6 1984 -1 0 - 1981 -1 0 - 1980 -1 0 - 1979 -1 0 - 1976 -1 0 - 1942 -1 0 7 2016 0 0 - 2004 0 0 - 1957 0 0 - 1945 0 0

It’s easy to beat guidance on days like these when we get clear skies and downslope flow with dewpoints in the 20s. Central Park SUNNY 66 25 21 W13G23

The core of the historic cold from the fall into the winter 76-77 was situated to our west around Ohio. That was their coldest fall combined with winter period. Also 3 of their top 5 of their coldest winters since the late 1800s occurred in the late 1970s. Most of the Arctic fronts around NYC during those winters were followed by W to NW flow. It’s probably why NYC didn’t get below -10 like they did in 1917-1918 which places in Ohio were able to surpass. The only times that NYC got below -10 were with NW to N flow down the Hudson Valley and an Arctic high over the Great Lakes. These late 70s into 94 Arctic outbreaks were accompanied by highs dropping further SW. The 1917-1918 and Feb 34 Arctic outbreaks had more NW to N flow down the Hudson Valley. Newark and Philly almost got down to -10 in the 1980s when they had more favorable flow that kept the best cold west of the Hudson. Time Series Summary for Cincinnati Area, OH (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 1 to Feb 28 Missing Count 1 1977-02-28 36.1 0 2 1918-02-28 37.8 0 3 1978-02-28 38.9 0 4 1963-02-28 39.7 0 5 1982-02-28 41.1 0 6 1936-02-29 41.2 0 7 1996-02-29 41.3 0 - 1970-02-28 41.3 0 8 1979-02-28 41.5 0 9 1994-02-28 41.6 0 10 1904-02-29 41.7 0 - 1893-02-28 41.7 0 Time Series Summary for Cincinnati Area, OH (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Season Mean Avg Temperature Missing Count 1 1977-1978 21.7 0 2 1976-1977 23.1 0 3 1917-1918 24.4 0 4 1962-1963 25.0 0 5 1978-1979 26.2 0 6 1935-1936 26.3 0 7 1904-1905 27.7 0 8 1981-1982 27.8 0 - 1903-1904 27.8 0 9 1919-1920 28.0 1 10 1969-1970 28.4 0 - 1963-1964 28.4 0

One of the first indications how cold 76-77 was going to be was NYC getting down to 50° at the end of August. Then the 29° in October. So a tie of the all-time monthly minimum in August and 2nd coldest in October. Then single digits during the first week of December. None of which has been able to be replicated since then. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Aug Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1986 50 0 - 1982 50 0 - 1976 50 0 - 1965 50 0 - 1885 50 0 2 1923 51 0 - 1912 51 0 - 1887 51 0 3 1940 52 0 - 1934 52 0 - 1895 52 0 - 1890 52 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1936 28 0 2 1976 29 0 - 1925 29 0 - 1887 29 0 - 1879 29 0 6 1940 30 0 - 1869 30 0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Lowest Min Temperature Dec 1 to Dec 7 Missing Count 1 1875-12-07 8 0 2 1976-12-07 9 0 3 1926-12-07 10 0 - 1882-12-07 10 0

The JAN-MAR 15 period still finished above 30.0 in NYC at 30.9. So it was comparable to DJF 14-15 at 31.4. Decembers have warmed too much since the 70s and 80s to allow a full winter to finish below 30.0° like 76-77 did. December 14 came in at 40.5° with 60s on Christmas Day. So the cold got started too late to compete against the really cold winters like 76-77. The cold also ended too quickly in 15 to have a memorable spring MAM cold ranking. In fact May 15 was the 2nd warmest on record in NYC. The cold was so impressive in 76-77 that it was the 7th coldest fall and winter on record. That kind of 6 month extended cold is no longer possible from the fall into winter. These days the early to sometimes mid fall is like another summer month. Temperatures in 1977 actually rebounded for a time in the early spring like a delayed thaw. Then the historic snowstorm occurred in May. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 1 to Feb 28 Missing Count 1 1869-02-28 34.7 122 2 1918-02-28 39.2 0 3 1881-02-28 39.9 0 4 1888-02-29 40.2 0 5 1872-02-29 40.7 2 6 1873-02-28 40.8 0 7 1977-02-28 41.1 0 8 1893-02-28 41.2 0 - 1884-02-29 41.2 0 9 1904-02-29 41.3 2 10 1905-02-28 41.4 0 - 1883-02-28 41.4 0

The main story is that we are adding more heat to the system faster than our technology can keep up with. So most of the time the first indication of a change or shift in our climate comes after it has already been observed. But with the introduction of AI, there is some hope that these longer range MJO forecasts will eventually be able to see stronger forcing and convection in the MJO 4-7 phases. While this has been an issue even during the La Ninas in recent years, the long range cold bias was more obvious this year since it was an El Niño. The paper below describes how this forecast error could be addressed with AI. https://www.nature.com/articles/s41612-023-00478-0 Over the past half-century, there has been an increasing trend in the magnitude and duration of the Madden-Julian Oscillation (MJO) attributable to the significant warming trend in the Western Pacific (WP). The MJO, bridging weather and climate, influences global and regional climate through atmospheric teleconnections, and climate models can predict it for up to 4–5 weeks. In this study, we use deep learning (DL) methods to investigate the predictability of the MJO-related western Pacific precipitation on a multi-month time scale (5–9 weeks). We examine numerous potential predictors across the tropics, selected based on major MJO theories and mechanisms, to identify key factors for long-term MJO prediction. Our results show that DL-based useful potential predictability of the WP precipitation can be extended up to 6–7 weeks, with a correlation coefficient skill ranging from 0.60 to 0.65. Observational and heat map analysis suggest that cooling anomalies in the central Pacific play a crucial role in enhancing westerly anomalies over the Indian Ocean and warming in the WP, thereby strengthening the Walker circulation in the equatorial Pacific. In addition, the predictability of WP precipitation is higher in La Nina years than in El Nino or normal years, suggesting that mean cooling in the central Pacific may contribute to increased predictability of the MJO-related WP precipitation on the multi-month time scale. Additional model experiments using observed sea surface temperature (SST) anomalies over the central Pacific confirmed that these anomalies contribute to enhanced MJO-related convective anomalies over the WP. The study highlights that DL is a valuable tool not only for improving MJO-related WP prediction but also for efficiently exploring potential mechanisms linked to long-term predictability.

Same old pattern longer range as it’s now only a brief cool down days 6-10 before we warm up again. Models continue to struggle with these week 2 forecasts which have been running too cold all winter. The underestimation of the Southeast ridge or WAR has been going on since 15-16. New run Old run