It was predicted to be mostly sunny Saturday over San Diego County except for some afternoon clouds over the mountains, the National Weather Service said.
A southwest flow has brought some drying to Southern California, but it will be short-lived as high pressure anchored across the Great Plains and Rockies returns a monsoon flow into the region early next week, forecasters said.
As more moisture arrives early next week, the chance for showers and thunderstorms may increase. Seasonally warm, mid-summer weather was expected to prevail, with some patchy night and morning coastal clouds, the NWS said.
High temperatures along the coast Saturday were predicted to be 75 to 80 degrees with overnight lows of 63 to 68. Highs in the western valleys were expected to be 84 to 89, and 90 to 95 near the foothills with overnight lows of 65 to 71. Highs in the mountains were expected to be 87 to 95 with overnight lows of 68 to 74, and highs in the deserts were predicted to be 106 to 111 with overnight lows of 84 to 89.
Moisture should gradually increase in Southern California on Sunday in response to a large thunderstorm complex in Sonora on Saturday night. This will lead to a better chance for thunderstorms Sunday afternoon, mainly just for the mountains.
Another stronger and deeper wave with a gulf surge arrives Monday morning. The deeper moist southeast flow could get rain started Monday morning along the desert slopes, with widespread showers and thunderstorms by the afternoon across deserts, mountains and areas west of the mountains, forecasters said.
Tuesday was looking similar to Monday, with a chance of rain outside the usual afternoon window, and drifting west of the mountains.
The flow turns a little more southerly on Wednesday, decreasing moisture and pushing any storm movement to the north or northeast, effectively diminishing chances west of the mountains, the NWS said.
This stagnant pattern was expected to continue into next weekend, with chances of thunderstorms mainly during afternoons in mountains and deserts.