PHOENIX (AP) - Tigers at the Phoenix Zoo are getting frozen fish snacks. Temporary cooling stations are popping up to welcome the homeless and elderly. And airlines are monitoring the soaring temperatures to make sure it's safe to fly as the western U.S. falls into the grip of a dangerous heat wave.
A strong high-pressure system settling over the region Friday and through the weekend will bring extreme temperatures to the already blazing Southwest. Notoriously hot Death Valley in California is forecast to reach 129 degrees, not far off the world-record high of 134 logged there exactly one century ago.
The National Weather Service predicts Phoenix could reach a high of 118 on Friday, while Las Vegas could see the same temperature over the weekend.
Temperatures are expected to soar across Utah and into parts of Wyoming and Idaho, where forecasters are calling for triple-digit heat in the Boise area through the weekend.
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.
Scientists say that the jet stream, the river of air that dictates weather patterns, has been more erratic in the past few years. It's responsible for weather systems getting stuck, like the current heat wave. Scientists disagree on whether global warming is the cause of the jet stream's behavior.
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.
But the company's smaller express planes flying out of the Phoenix area may be delayed if the temperature tops 118 because as the air heats up, it becomes less dense and changes liftoff conditions.
"The hotter is it, your performance is degraded," Lehmacher said. "We're monitoring this very closely to see what the temperatures do."
Officials at Salt River Project, the Phoenix area's largest electricity provider, also are closely monitoring usage in order to redirect energy in case of a potential overload.
Company spokeswoman Scott Harelson said he doesn't expect usage to get anywhere near SRP's record 6,663 megawatts consumed in August 2011.
"While it's hot, people tend to leave town and some businesses aren't open, so that has a tendency to mitigate demand and is why we typically don't set records on weekends," Harelson said.
Meanwhile, over at the Phoenix Zoo, animals from elephants to warthogs will be doused with hoses and sprayed with sprinklers and misters throughout the weekend.
The tigers will get frozen fish snacks while the lions can lounge on concrete slabs cooled by internal water-filled pipes, said zoo spokeswoman Linda Hardwick.
"And they'll all have plenty of shade," she said. "The keepers will all just be very active looking for any behavior changes, anything that would tip them off that an animal is just getting too hot."
In Las Vegas, two Elvis impersonators and a performer costumed as the iconic "Welcome to Fabulous Las Vegas" sign said they still planned to keep up their routine of working the tourist corridor in the broad daylight and turning in for the evenings, heat notwithstanding.
"We'd much rather fight with the sun than fight with the drunk people," Elvis impersonator Cristian Morales said.
Associated Press writers Robert Jablon in Los Angeles, Julie Jacobson and Michelle Rindels in Las Vegas, Michelle Price in Salt Lake City, and Susan Montoya Bryan in Albuquerque contributed to this report.
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