LOS ANGELES - A dangerous and potentially historic heat wave is forecast to tighten its grip on Southern California this weekend.
Temperatures are expected to reach 118 degrees in Woodland Hills, 114 in Pasadena, 112 in Burbank and 110 in Simi Valley on Saturday and Sunday, said David Sweet, meteorologist with the National Weather Service in Oxnard.
"Some of these temperatures could be the all-time record for the location," Sweet said.
Temperatures in many inland areas were well into the triple digits by 12:30 p.m., the Weather Service said.
Already on Friday, a record-high temperature of 109 degrees was set at Palmdale Airport, breaking the old record of 107 set on that date in 1955. Lancaster Fox Field tied a record of 108 also set in 1955.
The forecast prompted Gov. Gavin Newsom to issue an emergency proclamation aimed at shoring up California's energy capacity and staving off the kind of power outages and rolling blackouts that left tens of thousands of residents in the dark during the last big heat wave.
The California Independent System Operator, which runs the power grid for most of the state, has issued a statewide flex alert - calling for residents to voluntarily cut back their electricity consumption from 3 to 9 p.m. Saturday through Monday.
The heat is coming from a strong area of high pressure, "like a big dome of warm air, and it's sitting directly over the area," Sweet said.
That means temperatures also won't drop as much overnight as usual, dipping to the high 80s in the foothill areas and the 70s in most other places, he said.
"That does not allow the body to cool off very much, and that's one reason we're very concerned about this heat wave," Sweet said.
Officials are warning of an elevated risk of heat-related illnesses. People are advised to drink plenty of water and stay inside in air conditioning. Those who don't have air conditioning should try to go to a neighbor's home or cooling center.
Dozens of cooling centers opened across Los Angeles and Orange counties in recreation centers, public libraries, senior facilities and gyms.
"People can come in, have a seat, enjoy the coolness and have some cool water," said Renee Breaux, a Los Angeles city employee working Saturday at the cooling center at the South Los Angeles Sports Activity Center, in the 7000 block of South Figueroa Street.
"We didn't have anybody here yesterday, but I think we'll have some today," she said, as the temperature climbed into the 90s, just before the center opened at noon.
The city opened seven centers Saturday from noon to 8 p.m., most with capacities ranging from 33 to 44 people to accommodate social distancing requirements, said Jimmy Kim, superintendent of emergency management for the city's Recreation and Parks Department.
Kim said visitors to the centers are screened for temperature and any symptoms of COVID-19, including coughs and headaches. Their contact information also is noted so that they can be traced in the event of an outbreak of the coronavirus.
No one had been turned away from the centers because of COVID-19 symptoms, Kim said Saturday, but concerns about the disease are expected to keep the turnout low. On Friday, when six centers were in operation, only 33 people used them across the city.
"The last time we had the cooling centers open was about two weeks ago," he said. "With COVID, their use has been significantly reduced."
All who use the centers are required to wear face coverings. Hand sanitizer is provided, as well as masks if necessary, and maintenance staff routinely clean all high-touch areas, Kim said. Floor space is marked off to ensure social distancing.
Even with what are expected to be record temperatures for the rest of the weekend, Kim said, the cooling centers should have ample capacity. If necessary, he said, more centers can be opened on short notice.
"It's going to be a hot weekend," he said. "But we've done this before, even during COVID times. So we know how to run them and make sure we have enough places for people to come out and get cool."
People are also urged to check on those who are vulnerable, including older friends and neighbors, children and pets.
"High temperatures are not just an inconvenience, they can be dangerous and even deadly," Dr. Muntu Davis, L.A. County health officer, said in a statement.
Another concern is the possibility of fire. The National Weather Service has issued a red-flag warning, which indicates critical fire weather conditions, for the valleys and mountains of Southern California that will be in effect from 6 p.m. Sunday to 10 p.m. Monday, Sweet said.
In addition to the heat, relative humidities are expected to drop down into the single digits Sunday afternoon, with little recovery overnight.
In Santa Barbara County, a red-flag warning is in effect for the mountains and South Coast from 6 p.m. Saturday through 10 p.m. Monday because of the heat, low humidities and gusty "sundowner" winds, forecasters said.
The brunt of the heat is expected to hit the area Saturday into Monday. The high-pressure system will remain over the area through Monday but will weaken, allowing a bit more cooling in coastal areas starting Monday afternoon, Sweet said. But temperatures will remain above normal, and the valleys and inland areas will remain under an excessive heat warning through Monday, he said.
The triple-digit temperatures coincide with Labor Day weekend, which is typically one of the busiest beach days of the summer even absent a record-breaking heat wave.
As Southern California's coastal communities brace for an influx of visitors, public health officials are describing the weekend as a crucial test of whether Californians can slow the spread of the coronavirus by moderating their individual behaviors.
At 9:30 a.m Saturday, hundreds of beachgoers dotted the shore in Marina del Rey. Despite the morning hour, parking spots were hard to find, forcing families to walk multiple blocks, all while carrying plastic buckets, beach towels and umbrellas, to reach the beach.
Boaters and kayakers zipped along the water, while several games of beach volleyball were underway.
Beaches will remain fully open on Labor Day, unlike Memorial Day and the Fourth of July. But public health officials have cautioned they could order them to be shut down if they become overcrowded and people fail to follow the rules.
Those rules are: Wear a mask at all times unless you're in the water or eating or drinking, keep six feet apart from all those who don't live in your household and abstain from gatherings and group sports including beach volleyball.
"We have an opportunity this holiday weekend to change the trajectory of the virus in L.A. County," Barbara Ferrer, the county health director, said in a statement.
(Los Angeles Times staff writers Dakota Smith and Luke Money contributed to this report.)
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