San Diegans can expect occasional clouds through the weekend, but the question is how many? High-level winds from the southwest have been pushing clouds to Arizona. But [Wilbur Shigehara] said that, by the weekend, as these winds start to change direction, some wayward clouds settle in San Diego, bringing the possibility of thunderstorms in the mountain and desert areas.

"As these storms dissipate, their cluster of clouds spread. We need to know what direction the high-level winds are going in to determine where the clouds will go," Shigehara said.

Mountains and deserts will be mostly fair through tonight, becoming partly cloudy on Saturday. Mountain highs will be 72 to 78 degrees, with lows of 45 to 55 through Saturday. Desert highs will range from 97 to 102, with lows of 65 to 70 through Sunday.