It was a virtual tie, but the summer of 2021 (June, July and August) edged out the Dust Bowl year of 1936 by 0.01-degree Fahrenheit to become the hottest summer on record, according to a report issued by NOAA. You can find that report here: https://www.ncei.noaa.gov/….
The report noted that the Western states saw the greatest and most widespread heat, but it continued across the Northern tier of the country as well. California, Nevada, Utah, Oregon and Idaho each recorded their warmest summer on record, and 16 additional states had their top five warmest. Portions of Texas, Oklahoma and the Southeast states were the only ones to see areas of below-normal temperatures this summer.
The culprit was a stubborn ridge of high pressure across the Western U.S. It popped up in the first couple of days of June and almost stayed put through July before starting to weaken and allow more systems to move through North America in August. Record heat was recorded across the West with all-time-high temperature records falling in Oregon, Washington and Canada. The two months of heat set the West ablaze as wildfires popped up frequently, causing hazards for both humans and livestock. Smoke routinely spilled through the Northern Plains and at times lined up with wildfire smoke in Canada to spread across the Midwest.
In August, the more active pattern allowed some variable temperatures, but it was still a hot one. The month came through with an average that was 1.9 degrees Fahrenheit above normal, ranked as the 14th-warmest August on record. Heat shifted more from the Western states to the Northeast with the only cool spot in Texas.
Amazingly, with the commentary that DTN and other outlets were giving to the widespread drought across the West and Northern Plains, summer 2021 was wetter than normal. Total precipitation across the Lower 48 was set at 9.48 inches, 1.16 inches above normal, good for the eighth wettest on record.
The ridge was good enough to block a lot of storms coming from the Pacific, but there were still storms dropping south out of Canada and more general thunderstorms across the South as moisture from the Gulf of Mexico streamed northward to meet those systems. There was a very distinct line that separated the below-normal precipitation from the above-normal precipitation. That line was roughly from the Texas Panhandle to Lake Superior. North and west of the line was drier than normal, but south and east of it was wetter than normal. The wetter conditions more than made up for the dry and coincided with more of the nation's cropland than not, helping to keep yields high on a national-average perspective.
The exception to this line was in the Four Corners region. The ridge had a positive impact on the development of the monsoon, helping to draw more moisture from the Gulf of California northward. Drought was actually reduced by significant margins in Arizona, New Mexico and western Colorado as large areas of these states saw their drought see two to four categories of improvement, though it largely remains.
The heat and drought have been extensive across much of the West and Northern Plains, causing incredible injury to crops and livestock, pastures and rangelands, and causing higher culls of livestock as feed prices remained high.
Summer 2021 was certainly one for the books, and after 85 years, the record was finally broken.
John Baranick can be reached at firstname.lastname@example.org
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