Heat wave pushes temperatures above 119°F as 42 million U.S. residents face alerts
A shifting heat dome has driven extreme temperatures across the southern United States, prompting heat alerts for more than 42 million people and record highs of 119°F in California.
More than 42 million people in the United States are under heat alerts as a high-pressure system, described by forecasters as a "heat dome," moves westward. A weather station 16 miles southwest of Tecopa, California, recorded a temperature of 119°F on Wednesday, according to the National Weather Service (NWS).
The system, which previously produced extreme heat in the central and eastern U.S., is now expected to keep temperatures above 100°F across the South through Saturday before spreading to the Southwest, Intermountain West and northern High Plains over the weekend. Extreme heat warnings are active in parts of Arizona, California, Nevada and southern Utah, with some desert locations forecast to reach 120°F.
Warnings cover major metropolitan areas such as Phoenix, Tucson, Las Vegas, and portions of Los Angeles and San Diego, as well as national parks including the Grand Canyon, Zion, and Capitol Reef. Heat index values could climb to 120°F in southern Arizona and South Texas on Sunday.
The NWS HeatRisk monitor indicates that more than 2 million people in Arizona, New Mexico, Texas, Oklahoma, Louisiana, Mississippi, Alabama and the Florida Panhandle are at the highest heat-risk level, while an additional 24 million across the southern Plains and Gulf Coast face a "major" risk. > "Dangerous for anyone without adequate cooling or hydration," the agency warned, adding that prolonged exposure raises the likelihood of heat-related illnesses.
The service advises residents to drink plenty of fluids, stay in air-conditioned spaces, avoid direct sun, and check on vulnerable neighbors. It also recommends wearing lightweight clothing, limiting strenuous activity to early morning or evening, and seeking medical help for signs of heat exhaustion or heat stroke.
A strong cold front is forecast to bring cooler, less humid conditions to much of the eastern United States by next weekend, with temperatures expected to drop 10 to 20 degrees from current highs.