Thunderstorms could cause flash flooding across California on Sunday, including in recent burn areas in Los Angeles, Santa Barbara and San Luis Obispo counties. The potential for flash flooding is greatest in the mountains and the Antelope and Cuyama valleys. Heavy rainfall could cause debris flows in areas blackened by recent wildfires, including the Alamo, Whittier, La Tuna, Sand and Fish burn areas. Weather service meteorologist Curt Kaplan said a low pressure system parked off the coast is drawing monsoonal moisture from Mexico and Arizona. Showers are expected to taper off Monday as the system moves out of the area.

Source: Los Angeles Times September 10, 2017 01:18 UTC