Getting a bit cooler out there this week

Forecasters are expecting cooler weather across San Diego County this week, with a steady stream of high clouds continuing through much of Saturday.

Dense fog affected portions of the coast Saturday morning, with multiple reports of visibilities below 100-200 feet, the National Weather Service said.

“Nonetheless, temperatures should warm nicely into the high 70s and low 80s for most inland valleys, making this the warmest of the next seven days,” forecasters said.

Patchy dense fog may redevelop along portions of the coast Saturday night into Sunday morning, but coverage will likely be limited, forecasters said. Developing weak upper-level low pressure Sunday and Monday along the West Coast will force a drop in temperatures through Monday, when highs will mostly remain in the 60s west of the mountains.

“Onshore flow will reinvigorate the marine layer Sunday night, with more expansive low clouds affecting coastal and valley areas,” the NWS said. “Slight offshore flow may raise temperatures a touch on Tuesday as the trough swings east, but winds will be weak given marginal surface pressure gradients.”

A second trough will follow closely behind Wednesday and Thursday, bringing additional cooling and a return to an onshore wind regime, along with a deeper marine layer.

“This should make for a Thanksgiving Day that’s a little cooler than normal, with a slight chance for patchy light drizzle west of the mountains,” forecasters said.

Over the coastal waters, patchy dense fog is possible late Saturday afternoon through Sunday morning, with visibility below one nautical mile.