Although the San Diego County deserts will again experience near triple-digit temperatures on Saturday, it will be cooler elsewhere with a 20 percent chance of rain and thunderstorms in the mountains.
“High pressure aloft will weaken over the next several days, bringing cooler weather, increasing onshore flow, and a deepening of the marine layer,” according to the National Weather Service office in San Diego.
Highs Saturday are forecast to be 70 to 75 along the coast, 77 inland, 74 to 79 in the western valleys, 79 to 84 near the foothills, 79 to 88 in the mountains and 98 to 103 in the deserts.
Partly cloudy skies are expected throughout the region, with patchy fog overnight.
High pressure that has kept temperatures scorching are expected to weaken substantially over the weekend, dropping highs in the deserts to the mid 90s by Monday and highs in the western valleys to the high 70s, according to the weather service.