bluewave

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

Nice improvements from the 0z runs. We now have a shot at 3 days reaching 70° in the warmer spots from Wednesday into Friday. Looks like the backdoor stays just north of NYC into Friday. But sections just NE may get into onshore flow.

The NYC 3 coldest winters since the 28.4°in 76-77 were 93-94, 02-03, and 14-15. They were around 3° warmer than 76-77 at just under 32.0°. But we saw the big jump in winter temperatures since 14-15. So NYC may have warmed too much even see another winter like those below 32.0°. Our coldest winter since then was only around 36.0°. The one consolation of all the warmth over the last 9 winters is NYC hasn’t seen any winter DJF average as far above the baseline as 31-32 was yet. 15-16 started out on a pace to surpass the 31-32 magnitude above the baseline but it slowed down. So if we eventually see that much of a NYC winter departure in the coming years, then it would mean NYC would get its first 43.5° winter.

That was the only winter that I experienced which could be compared to the little ice age before the global temperatures took off like a rocket after 1980. Walking to the school bus stop was quite an experience. It was the last time NYC had a top 10 coldest winter averaging in the 20s.

Deep mixing now with Newark gusting near 60 mph with the sun coming out and steepening the low level lapse rates. Newark/Liberty CLOUDY 39 23 52 W43G59

That’s why all the EPS extended forecasts beyond day 15 defaulted to the past El Niño climo expectations of a trough in the East and a more robust Aleutian low. Instead we got the ridge south of the Aleutians and a very strong ridge in the East. This matches the La Niña background state over the past decade with frequent and amplified MJO 4-7 phases.

Good to see others also noticing how the teleconnection patterns aren’t as cold as they used to be.

The EPS has been running too cold day 11-15 and the GEFS has been closer to reality at least for us. But they both have been more than 5° too cold to our west. So these long range cold forecasts have been correcting warmer the closer in we get.

First time NYC ever had 50.00”+of precipitation from July into early March. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Jul 1 to Mar 9 Missing Count 1 2024-03-09 51.58 0 2 2012-03-09 49.54 0 3 1984-03-09 48.25 0 4 2019-03-09 48.12 0 5 2022-03-09 47.41 0 6 1914-03-09 46.20 0 7 1928-03-09 45.41 0 8 1976-03-09 45.36 0 9 1972-03-09 45.16 0 10 1890-03-09 44.27 0

Maybe graupel or small hail later today as we get some surface based CAPE. So gusty squall-like convection possible later today with gusts over 40 mph. Then we have a shot at 50-60 mph gusts tomorrow with the very steep lapse rates and increasing LLJ allowing deep mixing.

Warm minimums continue to dominate. The region is currently running +10 to +15 for the beginning of March. This has been the warmest on record for many locations like NYC. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Min Temperature Mar 1 to Mar 9 Missing Count 1 2024-03-09 42.2 0 2 2004-03-09 41.9 0 3 1979-03-09 41.7 0 4 1974-03-09 40.4 0 5 1998-03-09 40.0 0

The warm spots could see a few days this week making it to around 70° or higher. So this should add to the already high departures around +10 so far this month. The average highs will be in the low 50s by around the spring equinox. So the models showing colder for a time would mean upper 40s which isn’t too bad with the higher sun angle.

Yeah, the subtropical warming especially in the western ocean basins is more of a climate change signal than a -PDO signal even though both are overlapping. https://www.nature.com/articles/s43247-023-00839-w In this study, we evaluate the ocean warming pattern derived from four decades of satellite measurements. We find widespread strong subtropical ocean warming, concentrating mostly on the western ocean basins. In contrast to these observations, studies of paleoclimate suggest that the greatest ocean warming occurs at higher latitudes. By pairing the observed warming pattern with SST evolution in long-term climate simulations, we propose that the observed warming pattern is constrained by ocean dynamics of surface convergence (downwelling, subtropical gyres) and divergence (upwelling, subpolar gyres) rather than being dominated by internal variabilities, such as the PDO. This pattern emerges only at the early stage (a few decades) of anthropogenic warming when absorption of heat concentrates in the upper ocean. On centennial (for the Northern Pacific Ocean) to millennial (for the North Atlantic Ocean and Southern Hemisphere) timescales, when deep ocean water warms, the greatest ocean warming is expected to occur in the subpolar region, as indicated by paleo-reconstructions and the long-term and equilibrium climate simulations.

This is an important new study which highlights how quickly the WAIS could go if warm water gets underneath. https://www.cnn.com/2024/02/08/climate/west-antarctic-ice-sheet-melt-collapse-climate-intl/index.html CNN — Evidence from a 2,000-foot-long ice core reveals that the West Antarctic Ice Sheet shrank suddenly and dramatically around 8,000 years ago, according to new research — providing an alarming insight into how quickly Antarctic ice could melt and send sea levels soaring. Part of the ice sheet thinned by 450 meters (1,476 feet) — a height greater than the Empire State Building — over a period of just 200 years at the end of the last Ice Age, according to the study published Wednesday in the journal Nature Geoscience. It’s the first direct evidence that shows such a rapid loss of ice anywhere in Antarctica, according to the study’s authors. While scientists knew the ice sheet was bigger at the end of the last Ice Age than today, much less was known about when exactly that shrinking happened, said Eric Wolff, a glaciologist at the University of Cambridge in the UK and a study author. This study changes that, he told CNN. “We’ve been able to say exactly when it retreated, but we’ve also been able to say how fast it retreated.” Now it’s clear the ice sheet retreated and thinned very rapidly in the past, Wolff said, the danger is that it could begin again. “If it does start to retreat, it really will do it very fast,” he added. That could have catastrophic consequences for global sea level rise. The West Antarctic Ice Sheet holds enough water to raise sea levels by about 5 meters – more than 16 feet — which would cause devastating flooding in coastal towns and cities around the world. The study is “an excellent piece of detective work” about a major part of the Antarctic ice sheet, said Ted Scambos, a glaciologist at the University of Colorado Boulder. The key message is “the amount of ice stored in Antarctica can change very quickly — at a pace that would be hard to deal with for many coastal cities,” he told CNN. It was a surprise when the data revealed just how quickly the ice had thinned at the end of the last Ice Age, Wolff said. “We actually spent a lot of time checking that we hadn’t made a mistake with the analysis.” The West Antarctic Ice Sheet is particularly vulnerable to climate change, because the land under it is below sea level and slopes downward. When warm water gets underneath, it can melt very fast. “It can have a runaway process, and that’s evidently what happened 8,000 years ago,” Wolff said. What makes the findings so alarming, said Isobel Rowell, an ice core scientist at the British Antarctic Survey and a study co-author, is that once that runaway happens “there’s really very little, if anything, that we can do to stop it,” she told CNN. The crucial thing “is not to test it too far,” Wolff said, and that means tackling climate change. “We can avoid these tipping points still,” he said. The new data will help improve the accuracy of the models scientists use to predict how the ice sheet will respond to future global heating, the report says. David Thornalley, an ocean and climate scientist at University College London, said the study’s data was “striking.” He cautioned that as the study looked at a period 8,000 years ago, when climate conditions were different, the results aren’t a direct example of what could happen today. But, he added, they are still able to offer an “insight into the way that ice sheets can collapse.” The study comes as scientists continue to sound the alarm about what is happening to the Earth’s most isolated continent. For example, the Thwaites Glacier, also in West Antarctica, is melting rapidly. A 2022 study said the Thwaites — dubbed the Doomsday Glacier for the catastrophic impact its collapse would have on sea level rise — was hanging on “by its fingernails” as the planet warms. This new study adds to these concerns, Scambos said. “(It) shows that the very same processes we are seeing just beginning now, in areas like Thwaites Glacier, have played out before in similar areas of Antarctica and indeed, the pace of ice loss was equal to our worst fears about a runaway ice loss.”