Marine layer clouds were expected to remain in place today over much of the San Diego County coast and some of the adjacent valleys while high-level clouds stream northwest over Southern California, indicative of increasing monsoon moisture, the National Weather Service said.
High temperatures along the coast Saturday were predicted to be 71 to 76 degrees with overnight lows of 60 to 65. Highs in the western valleys were expected to be 77 to 82, and 88 to 93 near the foothills with overnight lows of 59 to 64.
Highs in the mountains were expected to be 88 to 96 with overnight lows of 63 to 70, and highs in the deserts were predicted to be 107 to 112 with overnight lows of 78 to 84.
Monsoon moisture was predicted to increase Sunday and beyond for daily chances of showers and thunderstorms, mainly over mountains and deserts, cooling a bit with temperatures below normal in most areas next week, forecasters said.
Sunday afternoon should see likely development of cumulus clouds over the highest elevations with even a 10% to 20% chance of showers and thunderstorms through early Sunday evening. Significant rainfall is not expected.
A better chance of afternoon thunderstorms was expected to arrive Monday, with a slight chance of showers and thunderstorms over the desert regions along with a slight risk of localized flash flooding, typical for monsoon season.