“It is somewhat unusual to have two strong, large-scale heat waves occur in quick succession in the same region of the country,” said Alex Lamers, Warning Coordination Meteorologist for the Weather Prediction Center (WPC).
While rare, Lamers mentioned it is not unprecedented.
“In fact, just last year, in June 2021, a significant heat wave affected the Southwest US in mid-June, followed by the extreme late June heat wave that produced all-time records in the Pacific Northwest and a national heat record in Canada,” Lamers recounted.
If you want to get technical, “summer” doesn’t start until tomorrow, even though the rest of the country has already been feeling like it in a big way.
If you think this year’s spring to summer transition has been blazing, you are right.
With more than 100 daily high temperature records expected to be broken this week across the country, it may not be a trend you want to see. But climate change is pointing toward it becoming the new normal, especially for the month of June.
“A clear upward trend is evident in average June temperatures over the past century,” Lamers stressed.
It means we will see more heat waves, stronger heat waves and more days with triple-digit temperatures.
One way it affects the US is by bringing much of the country warmer-than-normal summers.
“A comparison of the last 10 El Niño summers with the last 10 La Niña summers shows that the La Niña summers tend to be, on average, warmer over most of the contiguous United States, with the exception of the West Coast,” Lamers observed.
“Heat stress on the body has a cumulative effect, and people should be especially cautious in situations when heat is expected to persist for multiple days, and especially when there is a lack of cooling at night,” Lamers pointed out. “This means heat can even become a danger to your health after the hottest day in the heat wave.”
While last week’s heat wave started in the Southwest and spread eastward, this week the heat will begin in the northern Plains and then progress into the Ohio Valley, and down to the Southeast through the week.
“Like last week, we are mostly seeing the potential for daily temperature records, rather than monthly or all-time records,” Lamers emphasized.
Highs will run 10-20 degrees above normal this week. Around 70% of the US population will see a 90-degree or higher temperature this week and nearly 20% will see 100 degrees or higher.
CNN Meteorologist Haley Brink contributed to this report.