Triple-digit temperatures are expected for a second straight day around the Southland Wednesday as a heat wave continues to deliver a preview of summer during the last week of spring.
The forecast is raising fears of heat-related illnesses, strain on the power grid and the possibility of brush fires that could quickly spread in the hot and dry conditions.
The National Weather Service has issued excessive heat warnings that will be in effect through 9 p.m. Wednesday in the Santa Monica Mountains and Santa Clarita Valley. Earlier, the San Fernando and San Gabriel valleys were under the same excessive heat warnings — but they were downgraded Wednesday morning to heat advisories, the weather service said.
Meanwhile, excessive heat watches will be in effect for the San Fernando, San Gabriel and Santa Clarita valleys from Wednesday evening through Friday evening. During the advisories, temperatures between 90 and 102 degrees are expected. For the excessive heat watch, temperatures could reach 106.
In the Antelope Valley and Los Angeles County mountains — excluding the Santa Monica range — and in the Santa Ana Mountains and Foothills in Orange County, the excessive heat warning will last until 9 p.m. Friday.
The coastal area and downtown Los Angeles had been under an excessive heat watch until Tuesday evening, but even that part of town saw “dangerously hot conditions with temperatures in the 90s to around 100 degrees, especially inland and in the Hollywood Hills,” according to the NWS. The heat watch in the coastal area was originally expected to last through Wednesday, but it was cut short by the NWS.
In Orange County, inland areas including Santa Ana, Anaheim, Garden Grove, Orange, Fullerton and Mission Viejo will be under a heat advisory until 9 p.m. Friday, with temperatures in the 90s expected Tuesday.
Forecasters said the Antelope Valley in Los Angeles County could see temperatures ranging from 106 to 112 degrees during the heat wave, increasing the risk “for heat related illnesses, particularly for those working or participating in outdoor activities.”
Mountain areas are forecast to bake in temperatures of 95 to 108 degrees, with the hottest conditions on Tuesday and Wednesday. The valleys could reach as high as 109 degrees.
Both Palmdale and Lancaster reached 107 degrees on Tuesday, while Woodland Hills and Van Nuys reached 109, according to the weather service. The temperatures in Palmdale set a record for the date, topping the 105 mark set on June 15, 1966.
Northridge reached 108 degrees, while Chatsworth hit 107. Downtown Los Angeles recorded a high of 90 degrees.
A record for June 15 was also set in Anaheim, which reached 96 degrees, breaking the 2018 mark of 95.
“Strong high pressure over the southwest will lead to hot temperatures and mostly sunny skies across the region through the week,” according to the NWS. “Temperatures will be 10 to 20 degrees above normal, peaking today through Thursday.”
The weather service has already issued a red flag warning of extreme fire danger for southern Santa Barbara County due to the anticipated conditions Monday night through Wednesday morning.
Gusty conditions could become an issue in late afternoons in the Antelope Valley, creating “many hours of elevated to brief critical fire weather” each day, “due to the combination of gusty winds, humidities less than 15 percent and temperatures 102-112 degrees.”
The California Independent System Operator, which manages the state’s power grid, released a statement saying the agency “is closely monitoring weather conditions in preparation for excessive heat warnings in many parts of the state.”
“While we don’t anticipate rotating power outages at this time, we are headed into record-breaking high heat territory for certain areas beginning today through Friday, and we may call a Flex Alert if needed,” according to Cal-ISO.
A Flex Alert is a voluntary call for residents to conserve power during peak hours to reduce strain on the grid.
“We are working to give the public as much advance notice as possible that high heat could lead to a Flex Alert later this week, while raising awareness about the benefits of energy conservation during Flex Alerts,” according to Cal-ISO. “Californians have typically been very responsive to Flex Alerts, and we are always impressed and thankful for their efforts.”
The agency declared a “restricted maintenance operation” condition that will be in effect through Friday due to the forecasted high temperatures and demand. The declaration warns that all available resources will be needed to maintain supply, and calls on suppliers to defer scheduled maintenance on generators and transmission lines if possible.
The NWS warned that extreme heat will “significantly increase the potential for heat-related illnesses.”
“Be prepared to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun and check up on relatives and neighbors,” according to the NWS. “Young children and pets should never be left unattended in vehicles under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of minutes.”
Also due to the heat wave, the South Coast Air Quality Management District issued an ozone advisory through Saturday, predicting increased likelihood of poor air quality in many areas. Levels of ground-level ozone — the predominant summertime pollutant — are likely to reach unhealthy or higher air quality index levels throughout most of the Southland.
And, the Los Angeles County health officer issued an Excessive Heat Warning starting Monday and ending Saturday for West San Fernando Valley, East San Fernando Valley, East San Gabriel Valley, Santa Clarita Valley and Antelope Valley. The warning will be in effect through Thursday in the rest of the San Gabriel Valley, and from Tuesday through Wednesday in the Los Angeles basin.
The warning reminds everyone in the affected regions to take precautions to avoid heat-related illness, especially older adults, young children, outdoor workers, athletes, and people with chronic medical conditions.
Public Health officials issued the following recommendations to stay safe during high temperature days:
— Drink plenty of water throughout the day;
— Plan your day to avoid going out during the hottest hours, and wear sunscreen;
— Wear lightweight, light-colored clothes, and wear a hat or use an umbrella;
— Never leave children or pets in cars and call 911 if you see a child or pet in a car alone;
— Beware of heat-related illness, like heat stroke and call 911 if you or someone you know is experiencing high body temperature, vomiting, and pale and clammy skin;
— Check on those at risk, such as those who are sick, older adults, pregnant women, and children, and those who live alone; and
— If you are wearing a mask, avoid strenuous workouts wearing face coverings or masks not intended for athletic purposes.
“While it is very important that everyone take special care of themselves, it is equally important that we reach out and check on others, in particular those who are especially vulnerable to the harmful effects of high temperatures, including children, the elderly, and their pets,” said Los Angeles County Health Officer Muntu Davis. “High temperatures are not just an inconvenience, they can be dangerous and even deadly.”
County and city partners operate cooling centers during times of high heat. Residents who do not have access to air conditioning are encouraged to take advantage of free cooling centers. To find a location, visit ready.lacounty.gov/heat/ or call 211.
The city of Glendale will operate a cooling station through Thursday at the Pacific Community Center, 501 S. Pacific Ave., from 10 a.m. to 6 p.m. each day. The city of Carson will offer cooling centers Wednesday, generally from noon to 9 p.m., at the following parks: Anderson, Calas, Carson, Del Amo, Dolphin, Dominguez, Hemingway, Mills, Foisia and Stevenson, along with the Carson Community Center and Veterans Park/Sports Complex.
Los Angeles County residents and business owners, including people with disabilities and others with access and functional needs can call 2-1-1 for emergency preparedness information and other referral services.