Heat Kills Boy, 4, Trapped in Trunk of Car : Weather: Playmate is in fair condition after temperatures reached about 160 degrees inside auto. Tropical air brings record high of 104 to L.A.

Warm, tropical air from the south brought Los Angeles a record high temperature of 104 degrees Friday, claiming the life of a young boy in Riverside County and causing heavy thunderstorms, lightning, brush fires and a rare tornado warning in rugged portions of the Inland Empire.

A 4-year-old boy died and his 3-year-old playmate was in fair condition after they accidentally locked themselves in the trunk of a car while playing near their homes in the sunbaked Moreno Valley, police said.

Detectives said temperatures in the trunk reached about 160 degrees before the grandfather of one of the boys realized they were missing and pried the trunk open.

The dead boy was identified as Jared Victor Tootell. His playmate, Anthony R. Pullum, was in fair condition at the Loma Linda University Medical Center, a nursing supervisor said.

Meanwhile, lightning touched off a 480-acre blaze in the sparsely populated Cactus Valley area near Hemet, at one point threatening about a dozen homes and a camp attended by about 150 children, said Bonnie O’Connell, a spokeswoman for the Riverside County Fire Department. No injuries were reported.

By midafternoon, those homes were no longer threatened, O’Connell said. A second fire, about a mile away, consumed about an acre, and a smaller fire believed caused by downed power lines destroyed a mobile home in the back yard of a house in southeast Hemet, O’Connell said.

“We’ve got a lot of fires going on . . . small fires caused by the downed lines and lightning strikes,” she said.

Heavy rains and isolated flooding damaged several houses and cars.

A funnel cloud was reported at one point, though apparently it did not touch down, the National Weather Service said. A tornado warning was in effect through 4 p.m. Forecasters predicted further thunderstorms today.

In Los Angeles, the 104-degree high at the Civic Center smashed the record for Aug. 12 of 96 degrees, set in 1898, said Robert Baruffaldi, a National Weather Service meteorologist.

The overnight low of 75 was three degrees higher than the record minimum for the date, set in 1972. It was the third night in a row that the overnight reading broke records, Baruffaldi said.

Other high temperatures Friday included 110 in Monrovia, 109 in San Gabriel, 107 in Woodland Hills and Van Nuys, 106 in Burbank, 105 in Montebello, 104 in Pasadena, 102 in Anaheim and 100 in Long Beach.

Baruffaldi attributed the continuing heat to a high pressure system to the east, which is blocking normal air flows and allowing warm air to move up from the south and southwest.

“It’s preventing the usual cooler air from . . . coming off the ocean,” he said. “Instead, we’re having tropical air . . . which is warm to begin with. Since we’re staying warm overnight, it doesn’t take long for us to heat up and reach these record highs.”

Forecasters were expecting the pattern to continue, with only a slight cooling trend over the weekend. The high temperature in Los Angeles is expected to be 101 today (saturday) and 98 on Sunday, said Curtis Brack, a meteorologist with WeatherData Inc., which provides forecasts to The Times.

In the Sierra backcountry of Northern California, firefighters were expecting to bring two major brush fires under control. One fire destroyed at least two structures Friday in the rural town of Nevada City.

Elsewhere in the Sierra Nevada, residents of Twain Harte were allowed to return to their homes after being evacuated because of a fire that burned 1,400 acres of brushy timberland.

Firefighters were almost fully in control of the blaze late Friday and were expecting the douse the last embers early this morning.