Portions of San Diego County will be under a flash- flood watch Friday as nearly stationary low pressure trough increases the chances for potentially heavy showers and thunderstorms.
A National Weather Service flash-flood watch for the mountains and deserts is scheduled to remain in effect from noon until 8 p.m. Forecasters said thunderstorms would likely develop Friday afternoon.
"A slow moving low pressure system centered near Point Conception will maintain moisture and instability across portions of Southern California today," according to the weather service. "Slow moving thunderstorms this afternoon and early evening have the potential to produce locally heavy rainfall with flash flooding."
Forecasters said the valleys would have a slight chance of afternoon showers and thunderstorms, but they were not included under the flash flood watch.
A second low pressure trough could contain enough moisture for more rain into early next week.
Later next week, easterly flow between the low pressure trough and high pressure building over the Great Basin is expected to bring drier, warmer weather.
