The first summer heat wave in Southern California showed signs of breaking Tuesday, with the start of a cooling trend expected Wednesday thanks in part to increased onshore flow.

The area’s coastal cities were greeted with dense fog early Tuesday morning as meteorologists warned of suddenly reduced visibility for motorists, boaters and airlines. The low-hanging clouds, which are expected to thin by the afternoon, come with a temperature cooldown in the Los Angeles area after a muggy start to the week complete with high temperatures and poor air quality.

Temperatures in central L.A. will dip slightly Tuesday -- to 94 degrees -- but will fall below average over the next few days. Highs will fall to 87 degrees Wednesday and 82 degrees Thursday, according to the National Weather Service.

In the meantime, temperatures will remain above normal in the Valley communities, although not quite as high as they’ve been since Thursday, when the heat wave started. Those temperatures should be 3 to 5 degrees cooler in the coming days, meteorologists said.


“People should still take precautions,” said David Sweet with the weather service’s Oxnard station. ``"The valleys are still quite warm.”

Heat advisories for regions away from the coast have been extended through Tuesday in Los Angeles, Lancaster, Mt. Wilson, Ojai, Paso Robles, Santa Barbara, San Luis Obispo and Woodland Hills. Experts advise residents to limit outdoor activities, stay hydrated, find air-conditioned spaces and monitor children, elderly people and animals.

The poor air quality advisory has also been extended through Tuesday for the same areas, with the addition of Orange County.

“Elevated temperatures, which enhanced ozone formation rates, coupled with predicted atmospheric inversions that trap pollution near the surface may cause unusually high and persistent levels of ozone pollution,” the South Coast Air Quality Management District said.


Some parts of south Santa Barbara County, the 5 Freeway corridor from Castaic Lake to the Grapevine and the Southland’s mountains and valleys also remain under brief critical fire advisories by the weather service because dry and warm conditions paired with gusty winds are expected. Experts suggest using extra caution with potential fire sources in those regions.

City News Service contributed to this report.