Southern California To Swap Heat For Thunderstorms

LOS ANGELES (CBS/AP) — Southern California added the threat of fires and flooding to its misery on Thursday as forecasters predicted continued hot, muggy weather coupled with the chance of thunderstorms.

Areas of Ventura and northern Los Angeles County got some lightning and a little rain before dawn as a gust front from thunderstorms in Arizona tracked across the desert, said Rich Thompson, a meteorologist with the National Weather Service in Oxnard.

"It caused a little bit of a light show," he said.

That weather front was expected to move on but thunderstorms were forecast later in the day from another source: building monsoonal moisture.

Cloudier skies could drop temperatures a few degrees from Wednesday, when the desert town of Lancaster had a record high for the day of 111. However, Thompson said temperatures still will hit the triple digits in inland areas and "whatever we're gaining ... the increasing humidity is going to make it feel very uncomfortable."

Red flag warnings for extreme fire danger were to take effect in the afternoon in the Los Angeles and Ventura county mountains and the Antelope Valley because of the chance of dry lightning and gusty winds.

"Scattered thunderstorm activity is expected from this afternoon through this evening," according to a National Weather Service advisory. "The storms are expected to produce little rainfall, resulting in dry lightning strikes."

The lightning and winds that could gust at 50 miles per hour will combine with high temperatures "and very dry fuels" to create "the risk of fire ignitions and rapid fire growth," the advisory said. However, any thunderstorm Thursday night will be wetter than this afternoon's, reducing the risk of fire spread, according to NWS  forecasters.

Other areas could get more moisture, and flash flood watches were to be issued by late morning for mountains and deserts in San Bernardino, Riverside and San Diego counties. The storms won't be steady but could bring fierce downpours for 10 to 15 minutes at a time, Thompson said.

The chance of thunderstorms could extend into downtown Los Angeles and even some coastal areas by evening and continue into Friday morning, followed by a gradual cooling trend lasting through the weekend as high pressure weakens and low pressure moves in.