California to face high heat through Labor Day weekend

SAN DIEGO (AP) — Much of Southern California was under a warning for excessive heat Tuesday and forecasters said the torrid conditions will expand statewide.

Warnings went into effect in San Diego and Orange counties as well as in Southern California’s inland counties, and will spread north through the Los Angeles region and San Joaquin Valley on Wednesday.

“Strong high pressure centered over the Great Basin will bring a long duration heat wave beginning today and Wednesday and continuing through the Labor Day weekend,” said the San Diego office of the National Weather Service.

The state’s power grid operator issued an order restricting maintenance operations from Aug. 31 through Sept. 6 to help ensure that all generators and transmission lines were online.

The California Independent System Operator did not issue a call for voluntary conservation of electricity but said it would be monitoring the weather through the weekend. Its most recent call for voluntary conservation was on Aug. 17.

Residents were warned that the conditions could produce unhealthy levels of smog.

“Elevated temperatures increase emissions of chemicals leading to ozone formation and enhance ozone formation rates,” the South Coast Air Quality Management District said. “This long duration and intense heat wave will likely cause unusually high and persistent levels of ozone pollution.”

Excessive-heat watches will take effect later in the week in the San Francisco Bay Area, the Sacramento Valley and elsewhere in Northern California.