bluewave

08-09 was our last winter without some type of wild extreme.

It will be interesting to see. 08-09 finished closer to normal in the snowfall department. It was one of the few closer to average snowfall seasons in a sea of below and above normal snowfall extremes. So like you said, many here would be happy with a season like that after the last two.

Still early to guess at any analog types. But winters have been following a 1 or 2 year pattern for a while now. So it will be interesting to see if this winter reverts back to a snowier La Niña or does a rare 3 below normal snowfall seasons. We haven’t gone below normal for snowfall during 3 consecutive seasons since the late 90s. 19-20....18-19....Niña-like above normal temperatures and below normal snowfall 17-18.....16-17...La Niña above normal temperatures and snowfall 15-16..................Super El Niño with above normal temperatures and snowfall 14-15.....13-14....Record + North Pacific Mode with below normal temperatures and above normal snowfall. Also remembered as the record NEPAC warm blob winters. 12-13.....Niño-like above normal temperatures backloaded snowfall 11-12.....La Niña with above normal temperatures and below normal snowfall 10-11....09-10.....record -NAO and -AO with an El Niño then La Niña ....below normal temperatures and above normal snowfall.

With these Niña-like winter patterns, it really comes down to how far north the Pacific ridge extends. When it builds northward into Alaska, we can get -NAO intervals and snowier winters. But when that ridge flattens out north of Hawaii, we often get a strong +EPO/+NAO and well below normal snowfall. Near to above normal snowfall La Niña composite Below normal La Niña snowfall composite

Anything below +2 to +6 is considered cool by recent September standards. We would have to go back to 2013 to 2014 for departures under those levels. A continuation of less warm is the new cool. SEP....EWR...NYC...LGA 2019...+2.6....+2.4....+3.0 2018...+3.2...+2.7....+3.7 2017...+2.7...+2.5....+2.4 2016...+3.6...,+3.8...+4.7 2015...+5.2....+6.5...+5.0 2014..+1.6....+1.7....+1.3 2013...-1.0....-0.1.....-1.0 2012...+1.3...+0.8....+3.4 2011....+3.0..+2.0....+1.6 2010...+3.4....+3.1...+3.4

Big interior radiational cooling event in the forecast for next weekend. Temperatures should be even cooler than on Tuesday morning. So more fall-like temperatures after a warm start to September.

The NPM is remaining strongly positive even with the developing La Niña and -PDO. At least right now, we are getting more ridging out there than we typically see this time of year with a La Niña. But it’s still too early to know if this is a temporary pattern or can hold on into the fall and winter. Last winter the NPM dropped as the +EPO vortex took over.

The strong WAR without a deep trough in the MW/GL favors the SE and GOM like we are seeing with Sally. Notice how the trough remained up near Hudson Bay and couldn’t dig.We’ll have to see if the Euro stronger WAR verifies later in the week with the northern fringe of the remnant Sally moisture streaming into our area.

This could be our first year with 30 or more 90° days with none in the spring or fall. Monthly Number of Days Max Temperature >= 90 for LAGUARDIA AIRPORT, 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 2010 0 0 0 1 2 12 18 11 4 0 0 0 48 2018 0 0 0 0 4 4 10 16 4 0 0 0 38 2002 0 0 0 2 0 5 14 13 1 0 0 0 35 2020 0 0 0 0 0 5 19 10 0 M M M 34 1991 0 0 0 0 4 9 10 9 2 0 0 0 34 2016 0 0 0 0 3 1 15 10 3 0 0 0 32 1983 0 0 0 0 0 5 11 8 7 0 0 0 31 2005 0 0 0 0 0 7 10 10 3 0 0 0 30 1953 0 0 0 0 1 7 10 9 3 0 0 0 30

We have a pretty good idea that this will be the 5th consecutive winter with a La Niña-like base state. The North Pacific Ridge was able to extend NE into Alaska in 16-17 and 17-18 allowing for snowy and warm. The El Niño couldn’t couple in 18-19 due to all the record Niña-like SST warmth in the WPAC. So we had the La Niña ridge north of Hawaii and SE ridge for a mild and nearly snowless DJF. The record WPAC warmth in 19-20 set new records north of Australia. So we got a continuation of record MJO 4-6 amplitude and the Niña-like ridge north of Hawaii and SE Ridge. Warm and even less snowy overall than the previous year since we didn’t get the Nov and Mar snows. This fall we will be looking for clues as to which type of La Niña winter we will have this year. It often comes down to how much snow NYC can pick up in December. All the Niña-like Decembers with under 3.0” of snow in NYC since 1995 featured below normal snowfall seasons. While all above 3.0” finished normal to above normal. 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 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 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 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 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 2005-2006 0.0 T 9.7 2.0 26.9 1.3 0.1 40.0 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 1998-1999 0.0 0.0 2.0 4.5 1.7 4.5 0.0 12.7 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

Today was the 4th latest that HPN dropped below 55° after August 1st. Looks like NYC is on track for a 2nd latest first drop below 60 in a couple of days. HPN 12 Sep 7:56 am 57 50 77 ENE 6 10.00 CLR 29.92 1026.6 30.32 59 54 First/Last Summary for WESTCHESTER CO AP, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Difference 2005 06-23 (2005) 53 09-24 (2005) 51 92 2015 06-07 (2015) 51 09-21 (2015) 54 105 2011 06-15 (2011) 54 09-15 (2011) 50 91 1959 06-20 (1959) 50 09-12 (1959) 50 83 First/Last Summary for NY CITY CENTRAL PARK, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Difference 2016 06-14 (2016) 58 09-17 (2016) 59 94 1947 06-25 (1947) 58 09-17 (1947) 58 83 1966 06-13 (1966) 58 09-15 (1966) 51 93 2015 06-27 (2015) 58 09-14 (2015) 59 78 1996 06-03 (1996) 54 09-14 (1996) 57 102

https://www.njherald.com/news/20200909/summer-2020-was-second-hottest-on-record-in-new-jersey New Jersey experienced its second-hottest summer on record, continuing a long-term warming trend in the Garden State and across the planet that has seen sea levels rise and extreme weather become more common. The average temperature statewide soared to 75.3 degrees from June through August, ranking only behind 2010′s record-setting heat, according to a report released Tuesday by Rutgers University. Climate change is being felt increasingly in New Jersey, with the 10 hottest summers having all occurred since 1999, including seven since 2010, said David Robinson, the state climatologist and author of the report. A full list is below. “It’s indicative of what we’re seeing in other seasons in New Jersey, what we’re seeing nationally and what we’re seeing globally,” Robinson said. “It’s just another sign that climate change is here.” This summer’s milestone was not much of a surprise considering that July was the hottest month ever recorded in New Jersey. August 2020 was tied for the sixth-warmest August on record, and June was the 10th-warmest it’s been since record-keeping began in 1895.

50 years is not cherry picking. It represents the time of most rapid global warming as emissions have increased. The actual charts with trend lines are available at the NCDC site. New Jersey is one of the sates that you posted and summers have been warming at 0.3° F decade since 1895. This year was the 2nd warmest summer on record in NJ. Notice how many of the top 10 warmest summers have occurred in recent years. https://www.ncdc.noaa.gov/cag/statewide/time-series/28/tavg/3/8/1895-2020?trend=true&trend_base=10&begtrendyear=1895&endtrendyear=2020 201006 - 201008 75.7°F 126 202006 - 202008 75.3°F 125 201606 - 201608 74.9°F 124 200506 - 200508 74.8°F 123 201106 - 201108 74.6°F 122 201806 - 201808 74.4°F 121 201906 - 201908 74.4°F 121 199906 - 199908 74.3°F 119 201206 - 201208 74.2°F 118 200206 - 200208 74.0°F 117

It will be interesting to see how much longer this continues before it gets overpowered by warming. But how does agriculture cause increased rainfall and decreased temperatures? The team suspects it has to do with photosynthesis, which leads to more water vapor in the air. When a plant’s pores, called stomata, open to allow carbon dioxide to enter, they simultaneously allow water to escape. This increases the amount of water going into the atmosphere and returning as rainfall. The cycle may continue as that rainwater eventually moves back into the atmosphere and causes more rainfall downwind from the original agricultural area. Rong Fu, a climate scientist at UC Los Angeles, agrees with the team’s assessment. She also thinks that though human influence might be “greater than we realize,” this regional climate change is probably caused by many factors, including increased irrigation in the region. “This squares with a lot of other evidence,” says Peter Huybers, a climate scientist at Harvard University, who calls the new study convincing. But he warns that such benefits may not last if greenhouse gas emissions eventually overpower the mitigating effect of agriculture. Alter agrees, and says it’s unlikely that the large increases in U.S. crop production during the 20th century will continue. Other scientists have voiced concern that agricultural production could soon be reaching its limit in many parts of the world. “Food production is arguably what we’re more concerned about with climate change,” Mueller says. And understanding how agriculture and climate will continue to affect one another is crucial for developing projections for both climate and agricultural yields. “It’s not just greenhouse gasses that we need to be thinking about. While the cooling effect of irrigation mitigates global climate change on the regional scale, climate models suggest that regional warming attributed to the global trend will eventually overcome the magnitude of mitigation offered by irrigated agriculture. Farmers, who are partially buffered for now from more extreme heat, would quickly face increasing stress in that scenario. “Farmers in irrigated regions may experience more abrupt temperature increases that will cause them to have to adapt more quickly than other groups who are already coping with a warming climate,” says Kucharik. “It’s that timeframe in which people have time to adapt that concerns me.” The current study is the first to definitively link irrigation in the Midwest U.S. to an altered regional climate. These results could improve weather and climate forecasts, help farmers plan better, and, the researchers hope, better prepare agricultural areas to deal with a warming climate when the irrigation effect is washed out. “Irrigation is a land use with effects on climate in the Midwest, and we need to account for this in our climate models,” says Nocco.

The record breaking ridge centered near the Pacific Northwest Is a big change from the recent September decadal pattern. That area has usually experienced a trough during September. So it will be interesting to see if this temporary or has lasting potential through the fall and winter. This pattern keeps generating very strong highs that roll across the Northern US.

This is one of those times that a firehose Pacific Jet can help bring a series of cold fronts across the country.

The Euro has Canadian high pressure dominating into late September. So it’s possible that we had an early last 90° of the season back in late August. It would be the earliest last 90° at Newark since 2011. First/Last Summary for NEWARK LIBERTY INTL AP, NJ Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year First Value Last Value Difference Minimum 04-07 (2010) 08-08 (2011) 69 Mean 05-21 09-12 113 Maximum 06-17 (2014) 10-02 (2019) 170 2019 05-26 (2019) 90 10-02 (2019) 96 128 2018 05-02 (2018) 90 09-06 (2018) 98 126 2017 05-17 (2017) 92 09-25 (2017) 90 130 2016 05-25 (2016) 91 09-23 (2016) 90 120 2015 05-25 (2015) 90 09-09 (2015) 91 106 2014 06-17 (2014) 91 09-06 (2014) 95 80 2013 05-30 (2013) 93 09-11 (2013) 96 103 2012 05-28 (2012) 91 09-07 (2012) 90 101 2011 05-30 (2011) 92 08-08 (2011) 93 69 2010 04-07 (2010) 92 09-25 (2010) 90 170

Updated for 9-10. 9-10....Pt Lookout....6.47.....Massapequa....5.41...Wantagh Mesonet...4.64....Amityville....4.04....Copaigue....4.05

Record moisture instead of heat to go with the near record WAR for September.

With the exception of the super El Niño in 15-16 and March 18, the anomalous NEPAC Ridge has told the story of the winter. 13-14 and 14-15 were cold and snowy as the ridge set up over NW Canada. 16-17 and 17-18 were warm and snowy as the ridge location pulled back to the Aleutians. The last 2 winters were warm and nearly snowless as the ridge locked in just north of Hawaii. It’s no coincidence that my favorite snowstorms since 12-13 were in January 16 and March 18 as we finally got a -NAO/-AO pattern.

South Shore coastal sections missed out on the heaviest of the March snows in 2019. So they had two consecutive well below normal snowfall seasons. But they also did much better than the NYC area from 2013 to 2018. 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 2020-04-30 6.8 1 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 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 2020-04-30 4.8 1 2019-04-30 20.5 0 2018-04-30 40.9 0 2017-04-30 30.2 0 2016-04-30 32.8 0 2015-04-30 50.3 0 2014-04-30 57.4 0 2013-04-30 26.1 0

The bar is set pretty low. This was the first time that NYC had two consecutive met winters (DJF) under 5”. 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 Total Snowfall Missing Count 1 1997-1998 0.5 0 2 1918-1919 1.1 0 3 1972-1973 2.6 0 4 1931-1932 2.7 0 5 1991-1992 3.2 0 6 2001-2002 3.5 0 7 2018-2019 3.7 0 8 2011-2012 4.5 0 9 2019-2020 4.8 0 10 1989-1990 5.0 0

The dust bowl was a localized rather than global event. The heat and drought were amplified by the poor land use practices which lead to the extreme soil erosion. The modern localized summer cooler high temperatures in the corn belt are also a result of farming practices. https://www.journals.uchicago.edu/doi/10.1086/383102 Abstract We provide a new and more complete analysis of the origins of the Dust Bowl of the 1930s, one of the most severe environmental crises in North America in the twentieth century. Severe drought and wind erosion hit the Great Plains in 1930 and lasted through 1940. There were similar droughts in the 1950s and 1970s, but no comparable level of wind erosion. We explain why. The prevalence of small farms in the 1930s limited private solutions for controlling the downwind externalities associated with wind erosion. Drifting sand from unprotected fields damaged neighboring farms. Small farmers cultivated more of their land and were less likely to invest in erosion control than larger farmers. Soil conservation districts, established by the government after 1937, helped coordinate erosion control. This “unitized” solution for collective action is similar to that used in other natural resource/environmental settings. https://www.sciencemag.org/news/2018/02/america-s-corn-belt-making-its-own-weather The Great Plains of the central United States—the Corn Belt—is one of the most fertile regions on Earth, producing more than 10 billion bushels of corn each year. It’s also home to some mysterious weather: Whereas the rest of the world has warmed, the region’s summer temperatures have dropped as much as a full degree Celsius, and rainfall has increased up to 35%, the largest spike anywhere in the world. The culprit, according to a new study, isn’t greenhouse gas emissions or sea surface temperature—it’s the corn itself. https://news.wisc.edu/irrigated-farming-in-wisconsins-central-sands-cools-the-regions-climate/ New research finds that irrigated farms within Wisconsin’s vegetable-growing Central Sands region significantly cool the local climate compared to nearby rain-fed farms or forests. Irrigation dropped maximum temperatures by one to three degrees Fahrenheit on average while increasing minimum temperatures up to four degrees compared to unirrigated farms or forests. In all, irrigated farms experienced a three- to seven-degree smaller range in daily temperatures compared to other land uses. These effects persisted throughout the year.

This is a great example of what high enough snowfall rates can do.