A trough of low pressure was moving inland across San Diego County Sunday and was forecast to bring cooling through Tuesday, the National Weather Service said.
The marine layer was up another 400 feet from Saturday morning, which should provide more cooling into the valleys Sunday
Skies were clear over the mountains and deserts.
The marine stratus layer was extensive offshore and was likely be tough to clear the beaches Sunday, although some breaks were expected.
High temperatures in coastal areas Sunday were expected to be 66-71 degrees with overnight lows of 56-61, the NWS said. Western valley highs will be 70-75 and 74-79 in the foothills with overnight lows of 52-59.
Mountain highs were expected to be 76-86 with overnight lows of 49-57. Highs in the deserts will be 101-106 with overnight lows of 66-74.
Daytime highs were forecast to be below average for much of the week, with the coolest day on Monday, forecasters said.
The marine layer was expected to be deepest Monday night into early Tuesday morning.
Westerly winds were forecast to bring gusts of 35-50 mph near and below the mountain passes, and into the deserts for the next several days, combined with minimum relative humidity values of 10-20%. These conditions were expected to create elevated fire weather conditions at times.
