By early next week, the stifling heat dome will shift to the eastern Lower 48, baking the Ohio Valley, Midwest, Southeast and Mid-Atlantic. Highs could run 10 to 15 degrees above normal, with readings peaking in the upper 90s and heat indexes topping 100.
Records could be in jeopardy in many major cities, with conditions that could prove downright dangerous for older adults, the homeless and other vulnerable populations.
The National Weather Service has issued excessive heat warnings or heat advisories for more than 30 million residents from the Desert Southwest through California’s Central Valley into the weekend.
Phoenix and Las Vegas are under excessive heat warnings through Sunday, with temperatures expected to challenge records.
“In general, we typically see the first excessive heat warning in early to mid-June, so that in and of itself isn’t incredibly abnormal, but temperatures will be approaching records,” said Jenn Varian, a meteorologist at the National Weather Service office in Las Vegas.
Record highs are forecast for Thursday and Friday in Vegas — the number to beat Thursday is 108 degrees, and a high of 109 is expected. That edges out the record set in 1996. Saturday’s projected high of 109 degrees would tie a record. The average high in Las Vegas this time of year is about 100 degrees.
“The excessive heat is here. No changes in forecast thinking,” the Weather Service office in Las Vegas wrote in its online forecast discussion. “Temperatures will remain elevated to dangerous levels.”
The heat that is affecting Las Vegas covers most of the Southwest, encompassing southern and western Arizona; most of Southern California, including the Inland Empire and deserts; and California’s heavily populated San Joaquin Valley.
“High to Very High Heat Risk will be prevalent across the area through Sunday,” wrote the Weather Service in Phoenix, where an excessive heat warning is in effect through Sunday.