Mild, Clear Holiday Weekend in Store

The holiday weekend will begin with comfortable temperatures beneath a blanket of haze and smog, but an upper-level cold front that should move in Sunday will help clear the skies, forecasters said.

Morning low clouds and fog will actually begin diminishing on Saturday, particularly in the inland valleys, said Dave Beusterien, a meteorologist with WeatherData Inc., which provides forecasts for The Times.

High temperatures will range from the upper 60s along the coast to the low and mid-70s inland, Beusterien said. As the cold front begins to move south across Southern California Sunday afternoon, inland areas will begin to cool, he added.

High temperatures Sunday and Monday will be about 3 degrees cooler in San Bernardino, Riverside and Ontario, and the northern deserts could see drops of between 5 and 10 degrees, Beusterien said.

By Monday, as back yard grills swing into action for Memorial Day, the mercury will settle in the mid-60s to low 70s along to coast. Inland areas will be slightly warmer as highs reach the mid- to upper 70s.

The upper-level storm system heading this way will lower temperatures but produce no precipitation, Beusterien said. But it will help clear the air of pollutants.

An inversion layer at about 2,000 feet above the Los Angeles Basin on Thursday reduced visibility to about 3 miles in places, Beusterien said. What essentially happens with an inversion layer, Beusterien said, is air at upper altitudes is as warm or warmer than the surface temperature.