Thunderstorms are likely again Thursday afternoon in mountain and desert areas as Southern California nears the end of a wild week of weather.
Temperatures will remain warm and humidity levels will make for stifling conditions. The sweltering but erratic weather, which should taper off Friday, was caused by a high-pressure area coupled with a plume of moisture from Hurricane Linda heading off Mexico.
"Yesterday was the hottest day so far this year, but now we have more humidity," said NBC4 forecaster Crystal Egger. "It's going to be another rough one with oppressive heat."
Monsoonal thunderstorms began lashing portions of Southern California Wednesday afternoon, as they did a day earlier. The deserts and foothills had brief but fierce downpours, and lightning strikes set several small fires in northern Los Angeles County.
Concerns about close lightning strikes prompted the closure of beaches in Long Beach. In Orange County, swimmers were ordered out of the water at Sunset Beach.
The downpour also caused a mudslide that forced the closure of Agua Dulce Canyon Road near the Antelope Valley (14) Freeway.
Statewide Heat Wave
The Los Angeles Unified School Distict canceled all outdoor activities, including athletic events and practices, for Thursday and Friday due to the excessive heat. Athletic events scheduled for after 6 p.m. Friday are not canceled, but that might change.
Downtown Los Angeles reached a high of 101 degrees Wednesday while the airport in suburban Long Beach hit 103, breaking the old record for the day of 98 set in 1990, according to the National Weather Service. In San Diego County, Chula Vista's high of 99 was eight degrees above the 1990 record.
The Los Angeles Department of Water and Power recorded the highest demand for electricity so far this year -- 5,926 megawatts at 4:10 p.m. Tuesday, with an even higher reading expected Wednesday.
Throughout California, hundreds of cooling centers opened in senior centers and libraries around California as people looked for ways to cool off. Some schools dismissed students early amid a heat wave and air-quality alerts.