Heat wave brings record temps and a heightened wildfire risk to parts of the Western U.S.

A heat dome stretching from Arizona to Montana is expected to be relatively short-lived, National Weather Service meteorologists said.

A heat wave gripped large swaths of the Western U.S. on Saturday as temperatures hovered near record highs, heightening wildfire risks in areas that already are dry or burning and prompting warnings for people to stay inside.

A ridge of high pressure is holding heat close to the ground — what’s known as a heat dome — from Arizona to Montana, though the good news is that it will be relatively short-lived, National Weather Service meteorologists said.

Dangerous heat and warnings were plaguing the region, and the National Weather Service on Saturday forecast a number of cities that were expected to hit record highs.

By late afternoon, Las Vegas had reached 115 degrees Fahrenheit, the hottest temperature of the year; that’s just 1 degree off the daily record of 116. Phoenix was expected to reach 116, while El Centro, California, was expected to hit a record 118. Even parts of Montana were expected to broil, with a record 104 forecast for Great Falls.

Guests cool off in the wave pool at Mandalay Bay Resort and Casino in Las Vegas on Friday to escape a heat dome affecting much of the Western U.S.Ethan Miller / Getty ImagesIn Las Vegas, Saturday’s high was 10 degrees above normal, with meteorologists warning of dangerous heat through Sunday, when the high is expected to be 114, said weather service meteorologist Morgan Stessman.