After breaking March heat records in 14 states and the entire United States, a massive heat wave in the Southwest is spreading eastward and could end up being one of the most widespread heat waves in U.S. history, meteorologists and weather historians say.
Greg Gallina, a meteorologist with the National Weather Service Weather Prediction Center, said the situation isn’t going away just yet, probably not until the middle of next week as April begins.
“Basically the entire United States is going to be hot,” Galena said Monday. “The area of record temperatures is very large. That’s the really weird thing.”
Jeff Masters, a meteorologist at Yale University’s Climate Connection Center, said the thermal dome – in which high pressure acts like a pot lid, trapping hot air over an area – will keep temperatures in Flagstaff, Arizona, higher than the city’s previous March record for 11 or 12 consecutive days.
Galena said the dome’s eastward shift means temperatures in the southern and central Plains will be in the low 90s (mid 30s C) by Wednesday. Galena said a quarter to a third of the 48 mainland states will break records in March.
Chris Burt, a weather historian and author of “Extreme Weather,” said the physical scope of this heat wave could dwarf two other historical heat waves — one in 2012, another in the Midwest and Northeast, and another in 2021 in the Pacific Northwest. It might not have been as big as the 1936 Dust Bowl heat wave, Burt said, but that was a series of heat waves that lasted two months in the summer, not a major event like now.
Gallina said both the dust storm and the 2021 heat wave will be more intense, with higher temperatures and more harmful to people because they occur in June and July.
Galena said another saving grace for people in a heat wave is that it’s not as humid as when temperatures rise in the summer.
Temperatures reached 112 degrees (44.4 degrees Celsius) in four locations in Arizona and California on Friday, according to the weather service. Not only did this beat the record for the hottest day in March in the continental United States by 4 degrees (2 degrees Celsius), but it was just 1 degree cooler than the hottest day recorded in the lower 48 states in April.
Maximiliano Herrera, a climatologist and weather historian who tracks weather records around the world, compiled a list of the 14 states with the warmest March on record since the heat dome began: California, Arizona, Nevada, Kansas, New Mexico, Nebraska, Utah, South Dakota, Missouri, Iowa, Colorado, Wyoming, Minnesota and Idaho.
“In Mexico, even May records are being broken, with March records being broken by 14 degrees Fahrenheit, far more than July 1936, March 1907 or June 2021,” Herrera wrote in an email.
At least 479 weather stations broke March records from Wednesday through Saturday, according to the National Centers for Environmental Information’s weather station network. Herrera analyzed a wider range of data and said the true number is likely higher. Another 1,472 easier-to-break daily records were broken at the same time, the center said.
What’s happening, Masters and Galina said, is that the jet stream — which moves weather systems from west to east — is almost trapped to the west, like the storm that’s rolling through Hawaii, where people are experiencing heavy rains and flooding.
On Friday, an international group of climate scientists called World Weather Attribution determined that record high temperatures are “virtually impossible” and are 800 times more likely due to climate change caused by the burning of coal, oil and gas. The results of these activities increased temperatures by at least 4.7 degrees (2.6 degrees Celsius), said report co-author Clair Barnes, a scientist at Imperial College London.
Masters said the heat dome will be activated late next week: “We just have to give it time.”
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