We haven't even hit the dog days of summer yet and the hot temperatures are predicted to cause problems with travel nationwide.
Friday could be one of the hottest days ever recorded on Earth, as the western U.S. falls into the grips of a dangerous heat wave.
A strong high-pressure system settling over the region on Friday and through the weekend will bring extreme temperatures.
The mercury may hit 130 degrees F. in Death Valley, Calif. (The all-time high is 134 degrees.)
The National Weather Service is calling for 118 in Phoenix, and 117 in Las Vegas on Sunday - a mark reached only twice in Sin City.
Airlines are monitoring the soaring temperatures to make sure it's safe to fly.
Temperatures are expected to soar even as far north as Reno, Nev., across Utah and into parts of Wyoming and Idaho, where forecasters are calling for triple-digit heat in the Boise area through the weekend.
Meanwhile, there's more heavy rain expected in the Northeast today. West-central Pennsylvania is already dealing with major flooding, with 30 people requiring rescue from their homes.
Meteorologist Jeff Berardelli of CBS station WFOR-TV told "CBS This Morning" that the extreme heat "is going to be about as extreme as it gets. In fact, almost a once-in-a-century-type heat wave in the deep Southwest."
The National Weather Service warned that exceedingly hot temperatures are expected through Monday, with little relief expected at night, and that the heat wave has the potential to be a life-threatening heat event for those at risk.
Cities in Washington state better known for cool, rainy weather should break the 90s early next week, while northern Utah - marketed as having "the greatest snow on Earth" - is expected to hit triple digits. In Albuquerque, N.M., the mercury hit 105 on Thursday afternoon, the hottest it has been in the state's most populous city in 19 years.
"This is the hottest time of the year but the temperatures that we'll be looking at for Friday through Sunday, they'll be toward the top. We'll be at or above record levels in the Phoenix area and throughout a lot of the southwestern United States," said National Weather Service meteorologist Mark O'Malley. "It's going to be baking hot across much of the entire West."
Jennifer Smith, a spokeswoman for the National Interagency Fire Center based in Idaho, said crews are especially worried about wildfires igniting in the Four Corners region where the borders of Colorado, New Mexico, Utah and Arizona intersect.
Some of the strongest parts of the high pressure system are expected to be parked over the area through the weekend, where forecasters are calling for lightning but little to no precipitation, Smith said.
The hottest cities are taking precautions to protect vulnerable residents. Police are pleading with drivers not to leave children or pets in vehicles, and temporary cooling stations are being put up to shelter homeless people and the elderly on fixed incomes who hesitate to use air conditioning.
Officials said extra personnel have been added to the U.S. Border Patrol's Search, Trauma, and Rescue unit as people illegally crossing the border from Mexico into Arizona could succumb to exhaustion and dehydration. At least seven people have been found dead in the last week in Arizona after falling victim to the desert's brutal heat.
Even airlines are watching the mercury for any signs that temperatures could deter operations.
In June 1990, when Phoenix hit 122 degrees, several airlines, including America West, which later merged with US Airways, were forced to cease flights for several hours because the planes didn't have the data needed to know how they would fly in temperatures above 120 degrees.
US Airways spokesman Todd Lehmacher said the airline's fleet of Boeings can now fly up to 126 degrees, and up to 127 degrees for the Airbus fleet.