(Reuters) – Millions of people in the western and southern United States will bear the brunt of the first heat wave of the summer that begins on Tuesday, as temperatures are expected to rise above 37.8 degrees Celsius (100 degrees Fahrenheit) throughout the region.
From Northern California to Southern Arizona to Southern Texas, about 19 million Americans will spend the rest of the work week under excessive heat warnings and warnings issued by the National Weather Service (NWS).
The forecast calls for temperatures in the triple digits in many low-elevation locations, including Sacramento, Phoenix and Las Vegas, where the high is expected to reach 111 degrees Fahrenheit (44 degrees Celsius) on Thursday, the NWS said.
“High temperature anomalies of 20-30 degrees (Fahrenheit) above average are likely. Widespread temperature records are expected to be made or broken in many of the areas mentioned,” he added.
Meteorologists and local officials are urging residents to stay in air-conditioned areas, drink plenty of fluids and check on neighbors and relatives during the heat wave.
“Extreme heat is an invisible but dangerous consequence of climate change, and California’s outdoor workers, seniors and children are particularly vulnerable,” the California Environmental Protection Agency said in a social media post.
The heat wave is the first of the summer season in the United States, where higher than normal temperatures are expected over the next three months in many regions, according to the NWS.
Extreme heat overwhelms US power grids. In May, the North American Electric Reliability Corp, a group that sets reliability standards for North America, said large parts of the United States remain at risk of supply shortages due to heat this summer.
The prospect of hot weather could also mean more wildfires in California this summer, as arid and windy conditions fuel the flames. A 14,000-acre (5,665-hectare) wildfire, called the Corral Fire, has been 75% contained after forcing thousands of residents to evacuate east San Francisco over the weekend.
(Reporting by Brendan O’Brien in Chicago; Editing by Will Dunham)