bluewave

Yeah, parts of the Northeast can make a run on 100” of precipitation since last July as we approach the peak of the hurricane in September. Data for July 1, 2023 through July 21, 2024 Click column heading to sort ascending, click again to sort descending. CT PROSPECT 1.9 ENE CoCoRaHS 88.40 CT MIDDLEFIELD 1.4 W CoCoRaHS 87.54 CT OAKDALE 2.6 WNW CoCoRaHS 86.61 NY WEST POINT COOP 85.89 CT NORTHFORD 0.8 SW CoCoRaHS 85.18 CT BROOKFIELD 3.3 SSE CoCoRaHS 85.02 CT EAST LYME 0.5 SW CoCoRaHS 84.90 CT NORWICH 2.5 NNE CoCoRaHS 84.89 NY STONY POINT 0.7 NW CoCoRaHS 84.77 CT COLCHESTER 0.6 ENE CoCoRaHS 83.62

The one difference is that the PDO started positive and went to neutral in 16-17. This time we have a very strong -PDO. So not sure if the combo this time around would support some of the better snowstorms we had that winter despite the warmth. But even just a little better than the last few winters in the snowfall department would be nice.

The removal of the natural grasslands and poor farming practices were actually able to influence the circulation pattern of the entire Northern Hemisphere during that summer. https://news.ucar.edu/132872/1930s-dust-bowl-affected-extreme-heat-around-northern-hemisphere The 1930s Dust Bowl, fueled by overplowing across the Great Plains and associated with record heat and drought, appears to have affected heat extremes far beyond the United States. New research finds that the hot, exposed land in the central U.S. during the Dust Bowl drought influenced temperatures across much of North America and as far away as Europe and East Asia. That’s because the extreme heating of the Great Plains triggered motions of air around the Northern Hemisphere in ways that suppressed cloud formation in some regions and, in combination with the influence of tropical oceanic conditions, led to record heat thousands of miles away. “The hot and dry conditions over the Great Plains during the Dust Bowl spread extreme heat to other areas of the Northern Hemisphere,” said Gerald Meehl, a scientist with the National Center of Atmospheric Research (NCAR) and lead author of the new study. “If you look at daily record high temperatures, some of these areas are just now breaking the records that were set in the 1930s.” To determine the climatic impact of the Dust Bowl, the research team drew on observed high and low daily temperatures, as well as advanced computer models of the global climate system. They focused on the role of a teleconnection pattern, known as wave-5, that can regulate the meandering of jet streams and link far-flung weather patterns around the Northern Hemisphere during summer. The study was published in Scientific Reports. It was funded by the U.S. National Science Foundation, which is NCAR’s sponsor, as well as by the U.S. Department of Energy. TEASING OUT THE DUST BOWL’S INFLUENCE The Dust Bowl is widely viewed as one of the nation’s worst environmental disasters. Farmers in the early part of the 20th century plowed up millions of acres of native grassland across much of the Great Plains to plant wheat and other crops. When a multiyear drought struck in the 1930s, the exposed land became exceptionally hot and topsoil blew away, causing devastating dust storms as well as a health and economic catastrophe. The new research points out that extreme weather conditions extended far beyond the immediate vicinity of the Dust Bowl. Much of North America, northern Europe, and eastern and northeastern Asia experienced such heat that some record high temperatures of the 1930s are only now being exceeded as temperatures rise with climate change. Previous research pointed to patterns of warm and cool surface temperatures in the tropical oceans as triggering the drought in the Great Plains. These conditions were associated with a pair of multidecadal phenomena known as the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO). The question addressed by Meehl and his co-authors was whether such oceanic conditions could also explain the hot and dry weather around so much of the Northern Hemisphere, or if the Dust Bowl itself played a role. To tease out the influence of the Dust Bowl, the scientists first used an NCAR-based model of global climate, known as the Community Earth System Model (CESM). They ran a series of simulations on the Cheyenne supercomputer at the NCAR-Wyoming Supercomputing Center to see whether the IPO and AMO could fully account for the distribution of extreme daily high temperatures across three continents. But even though they set the model to capture the likely oceanic conditions of the time, they could not reproduce the high daily temperatures of the 1930s. They then turned to a version of the CESM atmospheric model that is a component of the DOE Energy Exascale Earth System Model, and set the model to isolate the influence of the extreme heat over the Great Plains during the 1930s. This time the results closely matched actual climate records, indicating that the Dust Bowl generated an atmospheric reaction that, in combination with conditions in the tropical Pacific and Atlantic, triggered extreme heat across vast areas of the Northern Hemisphere. “When you put the influence of the Great Plains Dust Bowl drought in the model, you get record-breaking heat in the areas where we saw them in the Northern Hemisphere during the 1930s,” Meehl said. INFLUENCE OF WAVE-5 Additional analysis of the simulations revealed the reason the Dust Bowl had such a pronounced effect on other regions: it generated a series of far-reaching vertical motions in the atmosphere. Such movements are known as a wavenumber-5 or wave-5 teleconnection — so named because it consists of five pairs of alternating high- and low-pressure features that encircle the globe along jet streams. In this case, the intense surface heating of the Great Plains created an upward motion of warm air, which then moved downward in surrounding areas, suppressing the formation of clouds over much of the northern U.S. and Canada. It also produced sinking air that suppressed clouds in other regions around the Northern Hemisphere, allowing more sunlight to reach the surface and resulting in soaring temperatures. At the same time, the pattern enabled warm, southerly winds to reach as far north as Scandinavia and eastern Asia. These winds contributed to the extreme heat over much of northern Europe and parts of eastern Asia. Meehl said the study helps illuminate how conditions on one part of the planet can affect the atmosphere thousands of miles away. Scientists have long known about the climatic influence of the vast tropical oceans, which pump out enormous amounts of relatively moist, warm air affecting weather patterns worldwide, as with El Niño. But it has proven more difficult to tease out linkages that arise from conditions over smaller areas of land in the midlatitudes, especially during summer. “This is a mechanism that arose in a unique way from human influence — not by burning fossil fuels but from plowing up the middle third of the U.S.,” Meehl said. “It’s possible that intense regional droughts in the future could also influence heat extremes in the Northern Hemisphere.” ABOUT THE ARTICLE Title: How the Great Plains Dust Bowl drought spread heat extremes around the Northern Hemisphere Authors: Gerald A. Meehl, Haiyan Teng, Nan Rosenbloom, Aixue Hu, Claudia Tebaldi, and Guy Walton Journal: Scientific Reports SEE ALL NEWS CONTACT David Hosansky Media Relations Manager 303-497-8611 TOPICS Climate, Weather TAGS News Release RELATED NEWS Dampening the “seeds” of hurricanes MON, 07/01/2024 - 12:00 Artificial climate control might become ineffective THU, 06/27/2024 - 12:00 Climate models underestimate carbon cycling through plants TUE, 06/25/2024 - 12:00

With a break in the 95° to 100° heat in the forecast, Hightstown in Mercer County only needs 2 more 95° days for the new all time record for a year. The previous record was set in 2002. The sea breeze influence has been so strong that places like Newark on the bay have been lagging behind. Harrison a little further from the bay made it to 101° during this most recent heatwave while Newark maxed out at 99°. Time Series Summary for HIGHTSTOWN 2 W, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2002 17 0 2 2024 16 168 - 1955 16 8 3 1953 14 0 4 2021 13 0 - 2018 13 1 - 2016 13 2 - 2010 13 4 - 1988 13 0 - 1949 13 0 5 2022 12 2 - 1999 12 0 - 1944 12 1 Data for January 1, 2024 through July 20, 2024 Click column heading to sort ascending, click again to sort descending. HIGHTSTOWN 2 W COOP 16 PENNSAUKEN 1N COOP 13 PHILADELPHIA/MT. HOLLY WFO COOP 12 EWING 3 WNW COOP 11 CALDWELL ESSEX COUNTY AP WBAN 11 TRENTON-MERCER AIRPORT WBAN 10 Trenton Area ThreadEx 10 SEABROOK FARMS COOP 9 HARRISON COOP 9 SOMERSET AIRPORT WBAN 8 MOORESTOWN 4 E COOP 7 NEW BRUNSWICK 3 SE COOP 7 NEWARK LIBERTY INTL AP WBAN 7 ESTELL MANOR COOP 7 SOUTH JERSEY REGIONAL AIRPORT WBAN 7 Newark Area ThreadEx 7 New Brunswick Area ThreadEx 7 Data for July 1, 2024 through July 20, 2024 Click column heading to sort ascending, click again to sort descending. TETERBORO AIRPORT WBAN 101 HARRISON COOP 101 TETERBORO AIRPORT COOP 101 HIGHTSTOWN 2 W COOP 100 NEWARK LIBERTY INTL AP WBAN 99 CALDWELL ESSEX COUNTY AP WBAN 99 SOUTH JERSEY REGIONAL AIRPORT WBAN 99 Newark Area ThreadEx 99 PENNSAUKEN 1N COOP 99

Will be interesting to see if we can get a new global high temperature record next week.

Just in terms of ONI, this reminds me of the transition from our last strong to super El Niño in 16-17. There was so much SST warmth leftover from that event in 2016, that the La Niña only achieved weak ONI for the 16-17 La Niña winter. It was a very warm winter since there was so much global heat left over from the previous winter being a super El Niño. The stronger La Niña didn’t arrive until 17-18. 2016 2.5 2.1 1.6 0.9 0.4 -0.1 -0.4 -0.5 -0.6 -0.7 -0.7 -0.6 2017 -0.3 -0.2 0.1 0.2 0.3 0.3 Super El Niño To weak La Nina Weak La Niña surrounded by residual super El Niño warmth

Yeah, human-induced land degradation was one of the leading causes of the Dust Bowl. https://www.pnas.org/doi/abs/10.1073/pnas.0810200106 The “Dust Bowl” drought of the 1930s was highly unusual for North America, deviating from the typical pattern forced by “La Nina” with the maximum drying in the central and northern Plains, warm temperature anomalies across almost the entire continent, and widespread dust storms. General circulation models (GCMs), forced by sea surface temperatures (SSTs) from the 1930s, produce a drought, but one that is centered in southwestern North America and without the warming centered in the middle of the continent. Here, we show that the inclusion of forcing from human land degradation during the period, in addition to the anomalous SSTs, is necessary to reproduce the anomalous features of the Dust Bowl drought. The degradation over the Great Plains is represented in the GCM as a reduction in vegetation cover and the addition of a soil dust aerosol source, both consequences of crop failure. As a result of land surface feedbacks, the simulation of the drought is much improved when the new dust aerosol and vegetation boundary conditions are included. Vegetation reductions explain the high temperature anomaly over the northern U.S., and the dust aerosols intensify the drought and move it northward of the purely ocean-forced drought pattern. When both factors are included in the model simulations, the precipitation and temperature anomalies are of similar magnitude and in a similar location compared with the observations. Human-induced land degradation is likely to have not only contributed to the dust storms of the 1930s but also amplified the drought, and these together turned a modest SST-forced drought into one of the worst environmental disasters the U.S. has experienced.

Since the 500 mb heights continue to rise as we warm, they get updated to the most recent 30 year normals which are the highest. If we could go back to a 1961-1990 period, then the current 500 mb height anomalies south of the Aleutians would look even more impressive with that older climo. They allow you to adjust the temperatures for the older climate normals. So the current winter temperatures look much more impressive since 15-16 using the colder 1961-1990 normals.

Models seeing the stronger Southeast ridge next week than in earlier runs. So this means that the stalled front to the south will come back north. This is when the chances for more widespread heavy convection will return. 70s dew points and 2.00”+ PWATS have been the norm this summer. New run Old run

This is the 1st time we have had such a strong and persistent Aleutian ridge over a 9 year period going back to the 1950s. Previous -PDO eras never had such a strong Aleutian ridge. So this is something new over the last 9 winters. The old -PDOs were more defined by their stronger -PNA troughs over Western North America. Since the -PDO from 1950s into 1970s didn’t have the strong Aleutian ridge, they also didn’t have a Southeast ridge. This is why the old -PDO winters were much colder in the East. We can remember cold -PNA patterns back then for the East. This new Aleutian ridge teleconnection has been an important driver of the Southeast ridge and record 9 warm winters in a row in parts of the East. Both ridges are function of the marine heatwaves in the MJO 4-7 regions generating this winter standing wave pattern through the stronger MJO 4-7 forcing. Plus the marine heatwaves east of Japan are also linked into this process. This process has also been warming the NW Atlantic leading to even stronger ridges in the East.

Only in the Great Plains as we regularly get much warmer summers than those were here in the Northeast. Time Series Summary for Allentown Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 1949 75.3 0 2 2018 74.9 0 - 2016 74.9 0 3 2005 74.6 0 - 1980 74.6 0 4 2019 74.4 0 5 2020 74.3 0 - 1943 74.3 0 - 1937 74.3 3 6 1994 74.1 0 7 2010 74.0 0 - 1983 74.0 0 - 1973 74.0 0 - 1966 74.0 0 - 1939 74.0 0 8 1995 73.9 0 - 1993 73.9 0 - 1988 73.9 0 - 1955 73.9 0 9 2011 73.8 0 10 2022 73.6 0 11 2021 73.5 0 - 2012 73.5 0 - 1944 73.5 0 - 1936 73.5 5 Time Series Summary for Burlington Area, VT (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 2020 72.3 0 2 1949 72.2 0 3 2018 72.1 0 4 2021 71.9 0 5 2005 71.5 0 6 2016 71.4 0 - 1995 71.4 0 7 1901 71.2 0 8 2022 71.0 0 - 1899 71.0 0 9 2012 70.9 0 - 1999 70.9 0 - 1895 70.9 0 10 1900 70.8 0 11 1955 70.6 0 12 2019 70.4 0 13 1896 70.3 0 - 1893 70.3 1 14 2023 70.1 0 15 1975 70.0 0 16 2013 69.9 0 17 2011 69.8 0 - 1994 69.8 0 - 1973 69.8 0 - 1959 69.8 0 - 1947 69.8 0 - 1944 69.8 0 18 1898 69.7 0 19 2015 69.6 0 - 2014 69.6 0 - 2010 69.6 0 - 1892 69.6 0 20 2003 69.5 0 21 2001 69.3 0 22 1993 69.2 0 - 1952 69.2 0 - 1937 69.2 0 23 2017 69.1 0 - 1988 69.1 0 - 1984 69.1 0 - 1894 69.1 0 24 2006 69.0 0 25 1991 68.9 0 - 1989 68.9 0 - 1938 68.9 0 Time Series Summary for Caribou Area, ME (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 2020 66.9 0 2 2021 66.2 0 - 2018 66.2 0 3 1973 66.0 0 4 1970 65.8 0 5 2014 65.7 0 - 2012 65.7 0 - 1995 65.7 0 6 2010 65.4 0 7 2023 65.2 0 - 1990 65.2 0 8 2016 64.9 0 9 2005 64.8 0 - 1975 64.8 0 - 1967 64.8 0 10 2019 64.7 0 11 2022 64.6 0 - 1999 64.6 0 - 1952 64.6 0 12 1979 64.5 0 13 1994 64.4 0 14 2011 64.3 0 - 1949 64.3 0 15 2006 64.2 0 16 1991 64.1 0 17 2001 64.0 0 - 1981 64.0 0 18 2017 63.9 0 - 1978 63.9 0 - 1974 63.9 0 - 1947 63.9 1 19 2008 63.8 0 - 1998 63.8 0 - 1955 63.8 0 20 2003 63.7 0 - 1944 63.7 0 21 1983 63.6 0 - 1939 63.6 0

NYC was able to get a decent 4.4” event on 2-17-18. This was a few days before parts of the area had their first winter and February 80° day on record. It was also the warmest February on record in NYC at 42.0°. Even with no cold air to speak of we got a nice BM track and decent high positioning for the event. The last time NYC had a 4” daily snowfall was on 1-29-22. So the last two winters have been a combination of record warmth and unfavorable storm tracks. We can get by with warm to record warm patterns. But when unfavorable seasonal storm tracks gets added to the mix there is very little we can do.

Yeah, I agree. Especially for the mid areas of the continent since the 15-16 super El Niño. We haven’t even needed severe cold around NYC metro for the great snowfall outcomes. Our area has seen a big uptick in 50°+ and 60°+ days in close proximity to our snowstorms. So while we have had numerous snowfall records since then, the overall snow cover days have been shrinking due to rapid melts. It really comes down to getting the Niña background to relax enough so we can get some decent BM storm tracks. The ridge that keeps pumping near the East Coast in recent years has forced the storm tracks too far west for areas other than the interior and high elevations to cash in. All we need is just cold enough with a good storm track.

I had to laugh when NYC was able to drop below 0° in February 2016 but couldn’t do it in February 2015. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 2016-02-01 59 44 2016-02-02 50 38 2016-02-03 59 42 2016-02-04 59 44 2016-02-05 44 31 2016-02-06 40 30 2016-02-07 47 33 2016-02-08 39 28 2016-02-09 36 27 2016-02-10 39 31 2016-02-11 31 18 2016-02-12 27 15 2016-02-13 22 6 2016-02-14 15 -1 2016-02-15 35 13 2016-02-16 54 35 2016-02-17 39 35 2016-02-18 36 27 2016-02-19 39 24 2016-02-20 61 39 2016-02-21 55 44 2016-02-22 52 38 2016-02-23 40 35 2016-02-24 60 36 2016-02-25 61 37 2016-02-26 39 27 2016-02-27 41 26 2016-02-28 60 38 Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 2015-02-01 36 20 2015-02-02 34 14 2015-02-03 26 13 2015-02-04 43 24 2015-02-05 42 14 2015-02-06 27 12 2015-02-07 40 25 2015-02-08 37 29 2015-02-09 29 25 2015-02-10 40 26 2015-02-11 34 22 2015-02-12 40 16 2015-02-13 21 8 2015-02-14 32 16 2015-02-15 25 4 2015-02-16 21 3 2015-02-17 27 14 2015-02-18 33 19 2015-02-19 27 8 2015-02-20 19 2 2015-02-21 32 13 2015-02-22 43 32 2015-02-23 38 8 2015-02-24 24 4 2015-02-25 37 20 2015-02-26 32 21 2015-02-27 30 18 2015-02-28 29 13

Yeah, whenever that Aleutian ridge can become more poleward and get pushed into the West Coast the Central US has been the focus of the relatively short but potent Arctic outbreaks since 14-15. It’s ironic that my strongest Arctic outbreak since the 15-16 super El Niño was on Valentine’s Day 2016. It was the only time NYC went below 0 since 1994. But it was a brief Arctic outbreak as has been the case across the U.S. So we can still generate significant Arctic cold over North America but the lasting power is much shorter than when it occurred in the past.

Yeah, that Arctic outbreak at the end of January 2019 was very impressive in the Midwest. While the warmth has dominated US winters since 15-16, there have been a few potent Arctic outbreaks. Another was in Texas during the 20-21 winter. The common theme is that the core of several of them have remained west of the Northeast closer to the center of the Continent.

We have effectively had 7 out of the last 8 winters with La Niña conditions. The weak El Niño in 18-19 and 19-20 wasn’t able to couple due to the very strong La Niña background state with the record WPAC warm pool. So we got a very strong Niña-like Aleutian ridge and Southeast ridge both winters. Warm MJO 5 tropical SSTs near 120E and marine heatwave east of Japan has been a common theme. If we count Niña-like background elements, then all of the last 9 winters would be included. December 2015 featured the record MJO 4-6 for an El Niño that strong. Plus this recent winter featured an unusual amount of Nino 4-7 forcing for such a strong El Nino also. The piece of the Aleutian ridge hanging on NW of Hawaii pushed the typical Nino +PNA ridge further east than usual. So there was stronger ridging into the Eastern US. The typical Nino trough was also dampened across the U.S. Southern Tier.

If the WAR verifies stronger than forecast again then those totals may begin to shifter further north over time as the month continues.

Thanks very much for posting that updated picture. It shows how the growth has even become more dense in recent years. The interesting thing is that the name attached to the photo is from a lead NWS forecaster in DC that used to be an active poster in our forum years ago. Ray is a really good guy that maintains a great winter storm archive. My guess is that he had to see the site in person since it has been running so much lower than surrounding sites. https://commons.wikimedia.org/wiki/File:2024-05-24_17_49_58_View_south_across_the_Central_Park_Automated_Surface_Observing_System_(ASOS)_in_Central_Park,_Manhattan,_New_York_City,_New_York.jpg

Yeah, it has been. First July that a place like SMQ had an average max 74.7° dew point and maximum average daily heat index of 98.0° . https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=76&network=NJ_ASOS&station=SMQ&season=jul&varname=feel&agg=max&year=1893&w=bar&hours=0-23&_r=t&dpi=100&_fmt=png

This was a top 3 warmest first half of summer across the Northeast.

Both the EPS and GEFS continue the active convection pattern going forward. We finally get a break from the major 95° to 100° heat. The front that lowers the temperatures and dew points here next few days comes back north with numerous waves of low pressure riding along it into late July.

A recent paper found it had a slight cooling effect on the Southern Hemisphere which only lasted through 2023. https://d197for5662m48.cloudfront.net/documents/publicationstatus/203287/preprint_pdf/44b2ee49f72f9858308861dbd4a9f8ed.pdf

The storm that moved through between 10:30 and 11:00 pm had the most lightning flashes since moving up here. The .89 for the day brings the rainfall total here up to 14th place for July so far. It was one of the few times that the 3rd round of storms on the day was the heaviest with the most lightning. Time Series Summary for NEW HAVEN TWEED AP, CT - Month of Jul Click column heading to sort ascending, click again to sort descending. 1 1971 8.73 0 2 2009 8.60 0 3 2023 8.22 2 4 2021 6.82 0 - 1953 6.82 0 5 1960 6.08 0 6 1956 5.25 0 7 2008 4.85 0 8 2019 4.83 0 9 2004 4.78 0 10 1969 4.73 0 11 1967 4.17 0 12 2018 4.06 0 13 1959 4.04 0 14 2024 3.84 14 15 1950 3.83 0

There is at least one study that found a slight cooling effect in the Southern Hemisphere which only lasted through the end of. 2023. https://d197for5662m48.cloudfront.net/documents/publicationstatus/203287/preprint_pdf/44b2ee49f72f9858308861dbd4a9f8ed.pdf