By CBSLA Staff

LOS ANGELES (CBSLA) — Thursday marked a day of unpredictable weather, as a heat wave that continues to bake most of the Western United States prompted the California Independent Systems Operator to issue a Flex Alert for the state, while thunderstorms brought downpours to the Southland in the morning hours.

People view the setting sun on June 15, 2021, in Los Angeles as temperatures soar in an early-season heatwave. (Getty Images)

The Flex Alert will be in effect from 5 p.m. to 10 p.m. Thursday to reduce stress on the grid and avoid power outages. The alert will take effect again from 6 to 9 p.m. Friday.

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Related: What Is A Flex Alert?

During that time, residents are urged to avoid using major appliances, turn off any unnecessary lights, set their thermostats to 78 degrees or higher and use fans for cooling.

“We’re seeing shortfalls in the neighborhood of 300 megawatts,” Mark Rothleder, Cal ISO’s chief operating officer, said Wednesday. “It’s not unusual for us to be able to get 300-plus megawatts of response from a Flex Alert. So that’s why we think a flex alert is necessary and gives us that buffer to absorb that 300 megawatt shortfall.”

Meanwhile, thunderstorms moved across the region Thursday morning, bringing scattered rainfall. The thunderstorms developed in Orange County and were moving northwest into the San Gabriel Valley and then the mountains, according to the National Weather Service.

Southland resident Shah Qhan said he was prepared to do his part, saying he thinks everyone should do their part to chip because power is always a major concern.

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The heatwave has had Shah and other moviegoers seeking shelter in a cool environment, with the added benefit of no longer having to wear a mask if they’re vaccinated since the state loosened most of the COVID-19 safety protocols as of Tuesday.

“We beat the heat this air conditioning and all that,” Qhan said. “This year, it’s like the cherry on top that we don’t have to wear a mask anymore and we’re going into the movies and all that.”

Shane Blond, another moviegoer expressed similar feelings.

“I’m super excited. It’s really the first movie I’ve seen in over a year now because of the pandemic and I’ve been wanting to do this for so long,” she said.

Earlier in the day Wednesday, some people were out early, exercising, before the hottest part of the day, while others flocked to the mall. For some business owners, like Gabriel Mora who owns Anytime Ice Delivery, business was booming.

“It’s been really crazy from 8 a.m. to 8 p.m and still I get after-hour deliveries from 10 to 11 p.m. It’s nonstop,” Mora said.

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Most of the state is in the midst of the heat wave, and a large swath of Southern California has been enduring triple-digit temperatures since Monday.