Showers are possible in San Diego on Saturday and could develop into thunderstorms later in the day, the National Weather Service said.
A radar image shortly after 11 a.m. showed a line of showers, and thunder could be heard in the north San Diego area.
Forecasters said an upper-level low-pressure system will move slowly over Southern California through Sunday, bringing cooler conditions as well as showers and thunderstorms, especially in the mountains. Flash flooding is possible in the mountains and deserts.
No advisories had be issued as of late Saturday morning.
