San Diego County inland areas were expected to slowly warm up Friday through Saturday, then cool through the end of next week with high temperatures falling to 10 to 15 degrees below average, the National Weather Service said.
A deeper marine layer should continue into next week with night and morning coastal low clouds extending well inland across most of the valleys, the NWS said.
Along the coast Friday, it was expected to be partly cloudy with high temperatures from 71 to 76 degrees, the NWS said. Inland valleys were expected to be partly cloudy with highs from 75 to 78. It should be mostly sunny in the mountains with highs from 80 to 90. The deserts were predicted to be mostly sunny with highs from 100 to 103.
A weak low-pressure system may move slowly toward the California coast through the weekend, the weather service said.
Cooling was predicted to begin to spread inland from the coast on Saturday and spread into inland areas on Sunday, forecasters said.
The system off the coast may move inland sometime during the early to middle part of next week. A second stronger low-pressure system from the north may move into the Pacific Northwest on Wednesday, then move slowly toward the south and remain across the western states through Friday.
High temperatures for inland areas for Thursday and Friday may fall to 10 to 15 degrees below average, the NWS said.
The chance for measurable precipitation for the mountains increases to 10% on Thursday, according to the weather service.
Northwest winds may gust near 20 knots at times Sunday through Sunday night in the outer coastal waters.
