An “extremely dangerous” heat wave is set to break daily temperature records across western and southern states through the holiday weekend, the National Weather Service warned.
The extreme heat comes as 28,000 were forced to evacuate their homes because of a raging wildfire in Northern California. The Thompson Fire in Oroville, about 65 miles north of Sacramento, had grown to 3,568 acres and was only 7% contained on Wednesday night.
California, southern Nevada and Arizona could see triple-digit temperatures on Thursday, with widespread excessive heat warnings, and it will be pushing the 100 degree mark in Tennessee, Arkansas and Louisiana.
The heat index, a measure of how hot it feels that takes into account humidity, could reach the 110s in the lower Mississippi Valley.
In total, more than 100 million people will spend Thursday under heat alerts.
Anyone holding Fourth of July celebrations might want to consider moving them inside — preferably somewhere with air conditioning.
“If planning to spend an extended amount of time outdoors this Fourth of July, be sure to use caution and act quickly if you see signs of heat-related illnesses,” the NWS said.
From then on in the West, it will only get hotter and more dangerous.
The National Weather Service forecasts temperatures between 110 and 115 degrees in inland California on Friday and Saturday. Parts of the desert southwest could reach 120 degrees.
Afternoon temperatures could reach the upper 90s and low 100s in the Northwest and parts of the Great Basin, the weather service said.
The weather service said that the levels of heat across the Mojave Desert, Sacramento Valley and San Joaquin Valley “could pose a risk to anyone if proper heat safety is not followed.”
Las Vegas is forecast to reach 117 degrees on Sunday and 118 on Monday, each higher than the city’s current all-time temperature record of 116.
The service advised people to stay hydrated, stay out of direct sunlight and inside an air-conditioned building where possible.
Records have already been broken: the city of Livermore, on the eastern edge of California’s Bay Area, reached 110 degrees, while San Rafael in Marin County, California, reached 100.
Parts of Arizona, Nevada and Texas just endured their hottest June on record.
Meanwhile, central states could face some severe thunderstorms this Fourth of July, with the greatest threat in parts of the Mississippi Valley and Southern Plains. There could be damaging lightning and strong gusts of wind.
The NWS issued a flash flood warning for Kansas City and surrounding areas for Thursday.