By CBSLA Staff

LOS ANGELES (CBSLA) – A Flex Alert will be in effect Friday evening statewide in an effort to relieve stress on the state’s power grid, as air conditioners across the Southland will be humming to stave off temperatures likely to reach triple-digits in many areas.

Tree trimmer Hugo Reyes cools off with a drink of water while working at Valencia Glen Park in Santa Clarita, Calif., on July 8, 2021. (Hans Gutknecht/Los Angeles Daily News/Getty Images)

The California Independent Systems Operator, the independent, nonprofit agency that oversees the state’s power grid, has issued a Flex Alert from 4 p.m. to 9 p.m. Friday.

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A Flex Alert is designed to reduce stress on the power grid and avoid the possibility of rolling blackouts. During that time, residents are voluntarily urged to avoid using major appliances, turn off any unnecessary lights, set their thermostats to 78 degrees or higher and use fans for cooling.

Last year, heat waves sparked rolling blackouts in California for the first time since 2001, and helped contribute to the spread of a historic number of wildfires up and down the state which destroyed thousands of homes and forced tens of thousands of people to evacuate.

An excessive heat warning will be in effect in the Antelope Valley through 9 p.m. Monday, with the National Weather Service predicting temperatures there to reach as high as 113 degrees.

A less severe heat advisory will be in effect for the Santa Clarita Valley from 10 a.m. Friday until 9 p.m. Sunday, with temperatures up to 105 degrees expected.

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Meanwhile, a heat advisory will also be in effect from 10 a.m. Friday to 9 p.m. Monday for Los Angeles County mountains, excluding the Santa Monica range. Forecasters said lower elevations could see temperatures of up to 106 degrees.

A heat advisory is also in effect now through at least 10 p.m. Sunday for the Inland Empire, including the cities of Riverside, San Bernardino, Ontario, Moreno Valley, Fontana, Rancho Cucamonga and Corona.

A continuing onshore flow will keep temperatures cooler along the coast.

The high-pressure system is expected to weaken early next week, but it will still be warmer than usual. Triple-digit temperatures are expected throughout next week in the Antelope Valley.

Residents without air conditioning at home can take advantage of cooling centers, with information on locations available here or by calling 211.

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(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)