Despite cooler temperatures, thunderstorms increase fire risk to parts of Southern California

After enduring a prolonged heat wave, Southern California can expect cooler temperatures and light showers along the coast Sunday with a chance for thunderstorms in mountain and desert areas, increasing the risk of more wildfires.

Despite the wet weather, the danger for more fires remains, warned meteorologist John Dumas, of the National Weather Service. In a pattern referred to as virga, the moisture in the middle layers of the atmosphere will fall as rain, but evaporate before hitting the ground, Dumas said.

"Unfortunately, the lightning can still" spark wildfires, Dumas said.

That could worsen conditions for fire personnel working around the clock to extinguish the Lake fire in Santa Barbara County, California's largest wildfire so far this year. That blaze has grown to 37,872 acres, but firefighters have worked to contain the blaze around the Santa Ynez and Los Olivos region where structures were threatened. The fire was 19% contained as of Sunday morning.

Crew members have made a "visible difference" on the south side of the fire in recent days, where flames could previously be seen from Santa Ynez and the Lake Cachuma area, Capt. Scott Safechuck, spokesperson for the Santa Barbara County Fire Department, said Saturday.

More than 3,000 firefighters and ground crews - assisted by controlled burns and water-dropping helicopters - have worked tirelessly to control the blaze. Those coordinated efforts have "really been successful for us eliminating a lot of the threat on the south side," Safechuck said.

The risk of fire-igniting by lightning prompted weather officials to issue a red flag warning until 9 p.m. Saturday for the mountain and foothill regions of Los Angeles County along with the Antelope Valley and valleys of San Luis Obispo and Santa Barbara counties, Ojai and Casitas Valley, according to the weather service.

Dumas said weather service officials have tools that can track in real time and model likely lightning strikes, which helps firefighters on the ground.

He said temperatures are expected to decrease by one or two degrees over the next few days, leading to "almost normal temperatures" by Monday or Tuesday before a new heat wave is expected to roll through Southern California.

This story originally appeared in Los Angeles Times .