More than 70 million are under heat warnings and advisories on Saturday through early next week as a potent heat dome sends temperatures soaring to levels the National Weather Service is calling "potentially deadly."
The big picture: The heat wave, made worse by a long-term, climate change-influenced drought, shows signs of eventually swelling into the middle of the country and then eastward through next week.
Why it matters: Extreme heat is the deadliest weather-related hazard in the U.S. each year, and climate change is making these events more likely, severe and long-lasting.
- The public health threat of this particular heat wave is especially elevated because of the high overnight minimum temperatures, which in many locations are breaking records. For example, at 1 a.m. local time Saturday morning, Phoenix was still at 100°F.
- "Extreme and deadly heat will continue through this weekend," the NWS forecast office in Phoenix stated, noting the "minimal overnight recovery." Forecasters noted that Phoenix may see its earliest-ever 90°F overnight low temperature.
Of note: The city has opened numerous cooling centers for those without access to air conditioning.
By the numbers: Heat advisories blanket nearly the entire state of Texas and Oklahoma, and extend as far east as Tennessee....
- These advisories and a more serious warning, known as an excessive heat warning, also are in place all the way to the West Coast, with triple-digit heat roasting California's Central Valley.
- Daily temperature records already have been set beginning Friday, and more are likely to fall Saturday and beyond. Overall, temperature departures from average during this heat wave are about 10 to 20°F