The Heat Is On With 3rd Day of Sun and Smog

After weeks of un-spring-like weather, the race to summer got a jump-start Monday as high temperatures continued, sending Southland residents scurrying for air-conditioned buildings and pushing smog to unhealthful levels in some areas.

Without the protection of a thick marine layer, temperatures hit 96 degrees in Monrovia and 93 in Van Nuys Monday, nine days before the official start of summer, reported WeatherData Inc., which provides weather forecasts for The Times. In Downtown Los Angeles, the mercury hit 90.

It was the third straight day of a mini-heat-wave that drove Angelenos indoors or to the beaches for relief from unrelenting sunshine and cloudless skies. On Sunday, temperatures peaked, with Woodland Hills registering 101 degrees.

The sultry weather was accompanied by worsened pollution, especially in the valleys and the Inland Empire, where thick smog shielded the mountains from view Monday. Officials declared air quality in the east San Bernardino Valley to be unhealthful, while in Los Angeles pollution was moderate.

Despite retreating temperatures forecast for today, the South Coast Air Quality Management District said Stage 1 smog alerts--the first of the season--would be in effect today for parts of the San Gabriel Valley, where pollution in the Los Angeles Basin is often heaviest. Any vigorous outdoor activity is unwise during Stage 1 alerts.

Conditions are expected to be unhealthful in the central city and the Santa Clarita Valley. The San Fernando Valley can expect moderate air quality, the AQMD said.

In Woodland Hills, Monday’s one-two punch of sweltering heat and deteriorating air quality produced “watery eyes and the normal nosebleeds” for a handful of students at Calabash Street School, said Principal Loretta Norwalt. Other children skipped handball and the swings in favor of quiet, shady spots during recess and lunch.

“Six of our rooms have air-conditioning, so that helps a lot,” Norwalt said. But three of the school’s classrooms rely only on open windows for ventilation, including one first-grade class where only 12 of 30 students showed up Monday.

Meteorologist Steve Maneikis of WeatherData said the brief hot spell has been precipitated by a stubborn high-pressure ridge hovering over Southern California.

“With that keeping the marine layer very thin and confined to the coast, it’s allowing you to heat up quicker early in the day, without the low clouds and early-morning fog,” Maneikis said. “Once the marine layer starts to return, which is what it looks like it’ll start to be doing here, you’re not going to be warming up so much.”

Maneikis forecast more sun for today, but said temperatures may cool slightly, especially along the coast. The rest of the week should see temperatures dipping back down into the mid-70s, he said.