Monsoonal moisture and warm weather are expected to bring thunderstorms to the desert and mountain areas of Southern California that could result in flash flooding.

The National Weather Service issued a flash flood watch Monday for most of the mountain areas across Southern California. Thunderstorms dumped rain and caused flash flooding on Sunday in northern Los Angeles County and downed trees in inland San Diego County.

Strong winds also produced a blinding dust storm in the Borrego Springs area. Lightning strikes sparked a small fire in the San Bernardino National Forest and caused a power outage to 4,000 homes.

A Temecula woman was killed Sunday after she lost control of her pickup truck on a freeway in heavy rain.