Monsoon moisture over San Diego County mountains and lower deserts was expected to maintain the chance for thunderstorms each afternoon this weekend, the National Weather Service said Saturday.
Drier air and building high pressure were expected to return early next week, followed by another moisture surge midweek. Closer to the coast, onshore flow could maintain a marine layer, with periods of low clouds and patchy fog spreading inland each night, the NWS said.
Temperatures should remain seasonably warm, along with high humidity.
High temperatures along the coast Saturday were predicted to be in the mid-70s with overnight lows in the mid-60s. Highs in the western valleys were expected to be in the mid-80s, and in the lower 90s near the foothills with overnight lows in the mid-60s. Highs in the mountains were expected to be around 90 with overnight lows in the mid-60s and highs in the deserts were predicted to be 94 to 104 with overnight lows in the upper 70s.
Moisture should decrease Monday and Tuesday as the ridge continues to expand and strengthen. The ridge will weaken and split by midweek, allowing a resurgence of moisture and thunderstorm chances over the mountains and deserts.
Monday and especially Tuesday were expected to be the warmest days, with the potential for at least moderate heat risk on Tuesday as high temperatures near 100 degrees.
A significant drying trend beyond Thursday was forecast.
–City News Service