Sneak Preview of Summer: Hot, Smoggy

Summer is officially two weeks away, but Southern California got a preview Thursday as a strong high-pressure system settled in to push temperatures into the 90s, foul the air and promise more of the same for the weekend.

The mercury climbed to 86 in Orange County, an “unusually high” temperature for this time of year, according to Betty Reo, a specialist with the National Weather Service.

“We have an upper level high pressure area that’s creating all these high temperatures, and it’s just planted itself over the Southland,” Reo said. “The prediction is that the weather will continue to be quite warm.” Elsewhere, the Los Angeles Civic Center recorded 95, up a dozen degrees from the day before. Palm Springs and other parts of the lower deserts had readings near 110.

Today should be a repeat, with temperatures reaching into the upper 80s in Orange County, and as high as 100 in the inland valleys and deserts.

Coastal areas should be warm and clear through the weekend but with some fog locally along the coast as marine air sneaks in along the edges. There were cooler temperatures and fog along some beaches on Thursday morning. In San Diego, dense fog made driving hazardous, especially in the inland mesa areas.

Thursday’s summerlike weather brought large crowds to Orange County beaches, with lifeguards estimating crowds of 8,000 at Laguna Beach and nearly 5,000 at Seal Beach by midday.

“The weather is warm, rather remarkable for early June . . . but what’s more remarkable is that we thought school was still in session,” said Seal Beach lifeguard Tim Dorsey.

“There are a lot of school-age kids out here on the beach today. It looks like this will continue through the weekend.”

Mountain resorts will have highs in the 70s and 80s. Upper Southern California deserts will have highs of 94 to 104, while the lower-desert highs will range from 106 to 112.

Smog levels were high Thursday as the high-pressure system produced a strong temperature inversion. The South Coast Air Quality Management District declared first-stage alerts in numerous sectors, including metropolitan Los Angeles, South-Central Los Angeles, Whittier and parts of the San Gabriel Valley, the San Fernando Valley and the Corona-Norco area.

A first-stage alert, meaning the air is unhealthful for everyone, is declared when the Pollutants Standards Index registers from 200 to 275.

Unhealthful air is forecast today for north and central Orange County, as well as the Saddleback Valley. People with emphysema, heart conditions, the elderly and the very young are urged to stay indoors if possible and avoid strenuous activity.

Thursday’s overnight low in downtown Los Angeles was 67 degrees. The high relative humidity was 70%, and the low was 26%.

Along Southern California beaches, surf is expected to run 2 to 4 feet at intervals of 12 to 14 seconds today and Saturday.

The onset of hot weather already is casting June in an unusual role. Normally, midday temperatures for the month are mostly in the 70s near the coast and in the 80s around the foothills. However, there have been some Junes in which 100-degree readings have been recorded.