Temperatures are expected to reach as high as 106 degrees Fahrenheit in the Dallas-Fort Worth area, and cities further west could see temperatures hit 120 degrees.
This high heat can turn deadly, and local officials are urging people to take the risk seriously.
In the Southwest, heat is expected to hit near-record highs. Tuscon, Arizona, can expect a high of 113 degrees on Sunday, and Phoenix may reach 116. Las Vegas is forecast to reach 110, and Death Valley will see a high of 116 this weekend.
A heat advisory covers most of Texas, virtually all of Louisiana and large swaths of Mississippi, Alabama, Oklahoma and New Mexico. Albuquerque is expected to reach 101 degrees on Saturday, and Oklahoma City is forecast to hit 106 degrees.
In the Southeast, temperatures will remain in the mid-90s but humidity will cause heat indexes to soar. Jackson, Mississippi, will see a heat index of 109, New Orleans will reach 110, and Mobile, Alabama, will approach a heat index of 114.
It is unlikely that monthly heat records will be broken in the region this weekend. But the temperatures are still high for the time of year, and their length is notable.
Heat waves, particularly in the Southwest, often carry relief with cooler temperatures overnight, but that effect is limited this weekend.
The high temperatures coincide with other unusual weather across the country. Tropical Storm Fay is bearing down on the mid-Atlantic, and parts of the Pacific Northwest are experiencing below average temperatures for July.
Heat warnings are different across the country
In the Southwest, “we use what we call a heat risk,” said Marvin Percha, a National Weather Service meteorologist. This assessment takes weather patterns and judges them against what is normal for the area. The rareness of an event guides its risk level.
This is different from other areas of the country, where heat indexes take bigger importance in heat warnings. A heat advisory, like the one covering the Southeast, uses heat indexes combined with actual temperature more than the temperature norms for the area.
While the advisory systems differ regionally, the message is the same: High heat expected in much of the South this weekend is dangerous, and residents should be prepared to take steps to be safe.
Staying cool during COVID-19
“If you have to be outside, try to limit your exposure and keep yourself well hydrated,” Percha said. “Seek air conditioned cooling centers if you have to.”