A slow warming trend in San Diego County was predicted to continue Wednesday, the official first day of summer, in advance of a low-pressure system approaching the West Coast, according to the National Weather Service.
Wednesday’s high temperatures were expected to be 69 to 73 along the coast, 73 inland, 74 to 77 in the western valleys, 75 to 80 near the foothills, 74 to 84 in the mountains and 99 to 104 in the deserts, forecasters said.
Cooler temperatures, more marine layer clouds extending into the coastal mountain slopes and breezy west winds for the mountains and deserts will arrive with the system of low pressure Thursday and Friday.
It should remain cooler on Friday with high temperatures for the mountains and inland valleys 15 to 20 degrees below average. The marine layer could deepen for Thursday night into Friday morning to around 3,000 to 3,500 feet with coastal low clouds covering most of the valleys early Friday morning if not extending onto the lower coastal mountain slopes.
The marine layer should slowly decrease in depth over the weekend, but with night and morning coastal low clouds still extending well inland into the valleys. Temperatures should be higher over the weekend with Sunday high temperatures for the mountains and inland valleys 5 to 10 degrees below average. High temperatures could be nearing average for the lower deserts.
Early next week, upper level troughing will weaken and allow for slight warming each day, with night and morning low clouds becoming more confined toward the coast and some adjacent valleys.
West-northwest winds may gust near 20 knots in the outer coastal waters each afternoon and evening through the beginning of next week.
Updated at 5:33 p.m. June 20, 2023
City News Service contributed to this article.
