Dangerously hot temperatures roasting the Southwest

(CNN) -- Imagine an icy cold day, Arizona. A chilly breeze, southwest California. Snow drifting slowly from low slate clouds, Las Vegas.

Now, keep those images close at hand. You're going to need something to help keep you cool as Mother Earth pours a big bucket of brutal heat on your head.

"Everybody's been saying how hot it is the last two days," said CNN meteorologist Indra Petersons. "This is nothing compared to what they're expecting this weekend."

The National Weather Service is warning residents from northern California, including Sacramento, all the way to southern Arizona of the possibility of intense heat through the weekend that could rival a 2005 heat wave that killed 17 people in the Las Vegas area.

Arizona and the California deserts seem to be in for the worst of it. Temperatures are forecast to rise as high as 122 degrees in California's Coachella Valley, as high as 129 in Death Valley and up to 118 in Phoenix.

Nevada won't get off easy either. In Las Vegas, the temperature is forecast to climb to 115. So emergency crews there are sending ambulances to stand by near the city's famed Strip, as well as at outdoor events, to help quickly treat people affected by the heat, according to CNN affiliate KLAS.

Crews will be dealing with heat exhaustion, but also may have to deal with tourists from paler climes thinking of returning from their desert vacation with a nice, bronze tan, Clark County Deputy Fire Chief Jon Klassen told the station.

"Somebody who's not used to the sun like we get here, comes here from another environment and thinks they're going to get that tan all in two days. They make themselves pretty miserable by eight o'clock at night," KLAS quoted him as saying.

The region is being baked by heat held in place by a high pressure dome that's blocking cooler air from the Pacific Northwest, Petersons said. That system won't begin to break up until early next week, she said.

The high temps come just a couple weeks before the 100th anniversary of what the National Weather Service calls the "highest reliably recorded air temperature on Earth" -- 134 degrees on July 10, 1913, at the Greenland Ranch in Death Valley, California.

It's unlikely that record will be broken this weekend, Petersons said, as the forecast calls for temperatures to reach a peak of 129 degrees on Sunday.