The gradual cooling trend that began Thursday will continue through the weekend, giving San Diegans their long-awaited relief from the heat and humidity.
"The heat wave is definitely over," National Weather Service forecaster Wilbur Shigehara said.
As an indicator of the downward trend, he noted that Lindbergh Field had a high of 78 on Thursday after recording an 84 on Wednesday.
"On the average, temperatures are down four or five degrees, and will continue to cool off over the weekend," he said.
Shigehara said the reason for the change is that the high-pressure system is gradually moving east and weakening. As it weakens, the hot desert air has more of a chance to pull the cool ocean air inland.
"This means the sea breeze will take more of an effect and cool us down," Shigehara said. "It also means the night and early-morning coastal low clouds will return."
Thunderstorms in the mountain and desert regions will continue throughout the weekend, Shigehara said, but will be limited as the high-pressure system weakens. High temperatures in the mountains will be in the 80s, with lows ranging from 55 to 65 degrees. Desert highs will be between 108 and 113, with overnight lows between 75 and 84.
Highs at the beaches will be between 69 and 74 degrees, with lows in the mid-60s.
"There is a hurricane named Javier about 1,450 miles southwest of San Diego," Shigehara said. "It has strong winds from 90 to 110 m.p.h. and is moving in a northwest direction. In a few days, Javier could bring the surf up, but I'm not optimistic it will happen over the weekend because of its distance from us."
Inland high temperatures will be in the 84- to 94-degree range on today, and 80 to 90 Saturday and Sunday. Lows will dip to the more-tolerable 60 to 64 degrees, compared to the 73-degree overnight lows experienced earlier in the week.