COLUMBUS, Ohio (WCMH) – As heat domes sat over the Pacific Northwest and New England last month, the lower 48 states recorded their hottest June on record, the federal government’s top climate agency said.
The National Oceanic and Atmospheric Administration reported Friday that the average temperature in the contiguous U.S. was 72.6 degrees Fahrenheit last month, 4.6 degrees above average. That’s the hottest in 127 years of recordkeeping, beating June 2016 by 0.9 degrees.
The western and northeast U.S. bore the brunt of June’s high temperatures as eight states – Arizona, California, Idaho, Massachusetts, Nevada, New Hampshire, Rhode Island and Utah – saw their hottest Junes on record.
And six states – Connecticut, Maine, Montana, Oregon, Washington and Wyoming – saw their second-hottest Junes.
“The historic heat in the Pacific Northwest has a recurrence of maybe once every 500 years or more,” explained NBC4 Meteorologist Ben Gelber. Cities like Seattle and Portland, Ore., saw their all-time high temperature records broken by as much as 7-9 degrees.
As the jet stream bent unusually far to the north over the region – resembling the Greek letter Omega – it moved slowly and dropped south across the Plains. It then allowed a second heat dome to build along the eastern seaboard.
This movement, Gelber said, atop drought-stricken land in the West, created extreme and persistent temperatures in a self-perpetuating heat wave.
“Much of the energy that might be used to evaporate water went straight back into the air and allowed temperatures to reach historic levels as far north as British Columbia,” he said.
Parts of Ohio also recorded abnormally high average temperatures last month. According to weather station data tracked by the Southeast Regional Climate Center, six northern Ohio cities saw top-10 hottest Junes.
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Columbus had its 18th-warmest June on record, according to the SRCC. Dayton saw its 17th-warmest and Cincinnati its 45th-warmest.
“We almost skipped over that nice little period at the beginning of June where it would be 85 degrees and sunny,” said NBC4 Meteorologist Liz McGiffin. “So, if nothing else, even on a comfort level we were seeing less of those nice comfortable temperatures and more of almost just the inconveniences that come with warming faster.”
“I feel like it’s just making (climate change) more and more undeniable and unavoidable,” she added.
Most climate scientists, Gelber said, believe climate change exacerbated the Pacific Northwest heat dome by amplifying an already historic heat wave.
“It’s like you have a running start on higher temperatures,” he said, “because temperatures have risen a couple of degrees” in the past century.
More than half the western U.S. is currently in “exceptional” or “extreme” drought, the highest of the five levels on NOAA’s drought monitor. Slices of central and eastern Ohio are experiencing “abnormally dry” conditions, the lowest level.
NOAA projects July to be warmer than normal in the western U.S. and most places above the Mason Dixon Line. Ohio is listed as having a 33-50% chance of having a warmer-than-normal July.