With only 12 days of summer remaining, September may be the best month of the year, assuming there are no tropical storms. A remarkably pleasant spell of weather is on the horizon, starting with a hot and dry weekend.
On Saturday there will be strong sunshine and daytime highs near 80. Some cloud may accumulate on Sunday, but it should remain dry and comfortably mild.
Scattered showers are possible late Monday, but more likely Tuesday as a weak system moves in from the Great Lakes region. Dry, calm conditions are expected Wednesday through Friday, with warmer than normal highs for mid-September.
The average temperature range as we move towards the autumnal equinox extends from pre-dawn lows around 50 to afternoon highs just above 70.
The Climate Prediction Center forecast for September 16-22 suggests above-normal temperatures and near-normal rainfall.
The latest report from the US Drought Monitor keeps Berkshire County in the moderate to severe zone, but the extreme drought zone in eastern Massachusetts is shrinking.
Heavy rain at the start of the week brought some relief here, with the highest totals reported in the South County – 4.2 inches in Great Barrington and Becket, 4.6 inches in Sheffield and 5.1 inches in Monterey and Tyringham – above average for the full month of September.
Pittsfield got nearly 3 inches, while North County’s totals were slightly lower.
“The problem when you have a big rain event is that a lot of it flows out,” said William Simpson, a National Weather Service meteorologist in Boston. “If you have 5 inches in a month, that allows it to seep into the ground. Rainfall figures can be misleading. Unfortunately, the overall impact will be minimal.
Extreme drought punctuated by flooding could become a more familiar pattern in New England as climate change intensifies.
At the University of Massachusetts Climate System Research Center, Associate Director Michael Rawlins said that since the 1950s there has been a 70% increase in the number of days the region experiences extreme levels of precipitation. “It’s a clear imprint of a warming world,” he said.
This weekend, Tropical Storm Kay is bringing excessive rainfall and flash flooding to parts of Southern California and the Southwest.
The dangerous heatwave is loosening its grip on central California and neighboring states, while noticeably colder air is spreading across the Rockies and the Plains.
But nearly 30 million residents, mostly in the Pacific Northwest, remain under excessive heat warnings, with increased fire risk from Washington state to west-central Oregon, where red flag warnings are in effect.
Heavy rain is expected from the Gulf Coast of Florida and the panhandle into coastal South Carolina and central Georgia before moving into the hills of North Carolina and Virginia.
As the week progresses, highs will be slightly below normal across much of the West.
• The 12-day heat wave in California and other western states was the most severe on record in September. Nearly 1,000 records have been broken. Salt Lake City (with an all-time high of 107), Sacramento (an all-time high of 116) and Reno (106) have broken their September records multiple times and by wide margins.
Sacramento and San Jose, where it hit 116 and 109 degrees on Tuesday, hit all-time highs. According to weather historian Maximiliano Herrera, it was “the greatest September heat wave ever west of the Rockies.”
Record temperatures extended from Arizona to Washington state and as far east as North Dakota.
Death Valley soared to 125 degrees on Tuesday, one degree below the world record high temperature.
“It was basically the worst September heat wave on record, certainly in Northern California and arguably for the state as a whole,” said UCLA climatologist Daniel Swain.
Christopher Burt, author of a book on extreme weather, called Tuesday “one of the hottest, if not the hottest, days in California weather history.” That day, California’s electricity demand hit an all-time high.
Redmond, Oregon, on Friday set a September record of 106.
The heat even erupted in western Canada, where the village of Lytton set a September record for British Columbia of 103.
• Amid scorching heat waves, brutal drought and widespread forest fires, Europe experienced its hottest summer on record, according to new data from the Copernicus climate change service. It was the second consecutive historic summer for the continent.
Officials have attributed thousands of deaths to the long stretches of oppressive weather. Crops withered and forests turned brown and barren as Western Europe was gripped by the worst drought in centuries.
Wildfires raged from the Caucasus Mountains to the Atlantic coast, with flames consuming about 50% more land than the previous record set in 2017.
• A recent analysis found that the burning of fossil fuels and other carbon-emitting activities made a July heatwave in Britain 10 times more likely.
Other research shows that the climate cycle of hot weather and dry landscapes can lead to the formation of ‘heat domes’ which deflect rainy weather and force the European continent to bake in the inevitable sun and heat.
“We expect these types of hot extremes to become more frequent and more severe due to climate change,” said Carlo Buontempo, director of the Copernicus service.
Globally, temperatures in August are tied for the third hottest on record, Copernicus reported. Heat waves have scorched much of China, making this the hottest summer in the country. Even the South Pole was warmer than usual for this period; sea ice extent around Antarctica reached a record high in July.
Human pollution by greenhouse gases is warming the planet at an unprecedented rate, according to the Intergovernmental Panel on Climate Change. Each of the past seven years ranks among the seven warmest on record.