Mostly sunny skies were forecast Sunday in San Diego County with moderate temperatures expected in advance of significant warming, which could continue into Wednesday, the National Weather Service said.
Periods of Santa Ana winds were expected, with the strongest winds occurring Monday morning into the afternoon, forecasters said. Winds may turn onshore late in the week allowing for cooling to spread inland along with a slight chance of light showers, the NWS said.
High temperatures along the coast Sunday were predicted to be 68 to 73 degrees with overnight lows of 43 to 49. Western valley highs were expected to be 72 to 77, and highs near the foothills were predicted to be 67 to 72 with overnight lows of 44 to 52. Highs in the mountains were expected to be 55 to 64 with overnight lows of 38 to 46, and highs in the deserts will be around 73 with overnight lows of 45 to 55.
The peak of the heat could occur on Tuesday west of the mountains when temperatures will run 10 to 20 degrees above normal, with highs in the mid-to-upper 80s inland. The current forecast leans to just 1 to 3 degrees shy of record-high territory at several sites.
Wednesday was predicted to be the transition day with winds turning back onshore during the day, but still very warm with inland areas mostly in the 80s. Lower deserts were likely to see peak heat on Wednesday.
An upper trough could move into the West Coast and begin to influence the weather further on Thursday with the better onshore flow then and significant cooling.
By Friday and next weekend, the trough was expected to dig into the region, the NWS said. The trough position may determine whether rain occurs in Southern California.
At county beaches Sunday night, a building swell of 3 to 4 feet was predicted to peak Monday and Tuesday. It could generate surf of 3 to 6 feet, with sets to 7 feet from Blacks Beach southward. Strong rip currents and elevated surf may create dangerous swimming conditions.