LOS ANGELES—In a preview of the summer ahead, temperatures began spiking June 15 in the Southland, beginning a heat wave that’s expected to bring triple-digit weather to many areas through June 18, possibly including downtown Los Angeles.
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 (NWS) has issued excessive heat warnings that will be in effect through 9 p.m. June 16 in the Santa Monica Mountains and San Fernando, San Gabriel and Santa Clarita Valleys, followed by a less severe excessive heat watch that will last until June 18.
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. June 18.
The coastal area and downtown Los Angeles will be under an excessive heat watch until the evening of June 15, but even that part of town will see “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 June 16, 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. June 18, with temperatures in the 90s expected June 15.
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.
“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.”
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 June 19, 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 ending June 19 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 June 17 in the rest of the San Gabriel Valley, and through June 16 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.
“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.