Another “ruthless” heat wave forecast for the West

Another wave of heat in inland California is expected to bring potentially dangerous conditions to the state, with weather officials warning that the Southwest will face “relentless” heat risks starting this weekend.

The National Weather Service is warning of a heat wave in the western U.S. in mid-July, including much of inland California, much of Nevada and parts of Arizona, Oregon and Idaho, and is expected to begin from Saturday to “Dangerously high temperatures” will be expected at least Tuesday.

“This event will continue for several days and will create hazardous conditions,” the weather service's warning said.

Alex Tardy, a meteorologist with the National Weather Service in San Diego, said: “We've just come out of a very severe heat wave over the past two weeks, and unfortunately we're really seeing warming again. Trend.” It's less severe, Tardy said, “but it's still a significant warming trend.”

Tardy said a thermal dome – a ridge of high pressure in the upper atmosphere – will form over the next few days, causing dramatic warming as high pressure essentially traps hot air.

“Thursday and Friday, the heat is starting to build over our area,” Tardy said. The heat is expected to peak over the weekend as the center of the heat is over inland California.

The duration of this heat wave is unclear, but the Climate Prediction Center warns that “above-normal temperatures are likely to continue into early August across much of the West and Great Plains.”

A heat advisory has been issued for much of inland Southern California, warning that “temperatures could reach very hot temperatures of 95 to 110 degrees” from Friday to next Wednesday. The weather service warns that overnight low temperatures are not expected to typically drop below 70 degrees.

In the Mojave Desert, a heat advisory has also been issued for Saturday and Sunday, with highs expected to range from 110 to 115 degrees; temperatures above 120 degrees are expected in Death Valley National Park, the warning said.

Officials say hot, dry periods will once again bring greater fire risks.

“Hot temperatures, dry fuels and occasionally gusty winds could lead to increased wildfire risk in parts of the Pacific Northwest, Great Basin and California,” the Climate Prediction Center warned.

The last heat wave lasted more than a week across much of California, causing a surge in wildfire activity across the state that engulfed several buildings, prompted evacuations and resulted in the first fire death of the year.