Scattered Showers Likely to Last Till Sunday

A mass of unstable tropical air invaded Southern California on Friday, bringing lightning, warm, muggy temperatures, scattered rain showers and the promise of more of the same throughout the weekend.

Thundershowers and lightning strikes swept across the Los Angeles Basin on Friday and were blamed for a series of power outages as well as a rash of small fires in Riverside and San Bernardino counties.

Rain pelted rush-hour commuters Friday evening, triggering traffic accidents and further snarling freeways and streets congested with motorists leaving Los Angeles for the weekend.

Eight people, six of them adult special education students, sustained minor injuries when a school bus skidded on wet pavement, glanced off a car and struck a tree at Mariposa Street and Santa Rosa Avenue in Altadena on Friday afternoon, fire officials said.

An unidentified Los Angeles police officer suffered minor injuries Friday afternoon when his motorcycle skidded into a rut and overturned on the rain-slick Simi Valley Freeway near the Santa Susana Pass. The officer was returning from the funeral of another motorcycle officer who was fatally injured in a traffic accident Wednesday.

A spokesman for Southern California Edison Co. said 131,000 customers suffered power outages as a result of lightning strikes, most of them in San Bernardino, Riverside and eastern Los Angeles counties.

During a six-hour span in the San Bernardino National Forest, 3,200 lightning strikes were recorded. “I guess we’ve had about 20 or 30 fires but none of them major,” Forest Service dispatcher Mark Luker said.

Showers and thundershowers are expected throughout the Southland today, with rainfall varying from about one-tenth of an inch near the coast to more than half an inch in foothill and mountain communities.

“The last, lingering showers will fall on Sunday morning,” said Steve Burback, a meteorologist with WeatherData, Inc., which provides forecasts for The Times. “By Sunday afternoon, skies should be mostly clear.”

Burback said the wetness is coming from a large low pressure system off Baja California that is drawing tropical moisture into Southern California. A high pressure system over the Rockies is feeding down-slope winds that are heating by compression as they sweep westward toward the California coast.

By 5 p.m. Friday, rainfall from the storm measured 0.07 of an inch in Newport Beach and 0.02 in Glendale, Monrovia and Northridge.

The high temperature at the Los Angeles Civic Center on Friday was a muggy 91 degrees, 7 degrees below the 98-degree record for the date, set in 1965. The relative humidity Friday ranged from a comfortable low of 26% to a soggy high of 89%.

Burback said that while the humidity will remain about the same today, temperatures should be somewhat cooler, with highs ranging from the upper 60s along the coast to the middle 80s farther inland.

As skies clear on Sunday, temperatures will drop, Burback said, with highs in the 60s in beachfront communities.