Cool Mornings : Forecasters Expect Fog, Low Clouds

Typical spring weather is forecast for Southern California through the weekend.

Morning fog and low clouds are expected to give way to clear skies and warmer temperatures this afternoon, but a scattering of afternoon and evening thundershowers are expected in the mountains and deserts, beginning Saturday and continuing into next week.

“A high-pressure system that kept conditions relatively dry Thursday is weakening and beginning to drift away to the north,” said Matt Sullivan, meteorologist-spokesman for Earth Environment Service, a private forecasting firm based in San Francisco.

“Tropical moisture is moving into Southern California from the south. This is an unstable situation and should bring on more thundershowers with no difficulty at all.”

The high at Los Angeles Civic Center on Thursday was 75, with relative humidity ranging from 55% to 84% during the day.

In Santa Ana, the high reached 72 on Thursday after an overnight low of 61. But the National Weather Service said it should be about five degrees warmer this afternoon, rising to 82 or 83 on Saturday and Sunday.

Fog at the Beach

Beach weather, meanwhile, is expected to include fog and drizzle this morning, with partial clearing during the afternoon, highs from the upper 60s to the low 70s and an afternoon sea breeze rising to 15 m.p.h., with surf breaking at three feet in most places and water temperature only a few degrees cooler than the air.

The high in Newport Beach on Thursday was 63, only four degrees warmer than the morning low.

Weekend yachtsmen were warned of fog banks that can be expected to lurk just offshore most mornings. These conditions should clear by noon or so, with afternoon winds west to southwest rising to 15 knots and two-foot seas along the coast from Point Conception to the Mexican border, changing to a 13-knot northwest winds and three-foot seas farther out.

The San Bernardino and San Gabriel mountains are expected to be partially cloudy with a chance of thundershowers most afternoons with temperatures in the upper 70s to lower 80s at resort altitudes. Thundershowers are also forecast for the deserts, with temperatures in the northern deserts rising to the upper 90s and southern desert temperatures about 10 degrees higher.