“Triple-digit high temperatures will be common over the hottest valleys, foothills and desert between Saturday and Monday,” the National Weather Service (NWS) said over the weekend. “Very warm conditions are likely to continue Tuesday through Thursday with increased clouds and possible monsoonal showers and thunderstorms.”
Highs on June 28 were expected to reach at least 82 degrees in downtown Los Angeles, 96 in Van Nuys, 110 Lancaster and 104 in Santa Clarita, according to the NWS.
An excessive heat warning was in effect through 9 p.m. Monday in the Antelope Valley, the Santa Clarita Valley and Los Angeles County mountains, excluding the Santa Monica range. Forecaster warned that those areas will face “dangerously hot conditions with temperatures up to 110 expected.”
“Extreme heat will significantly increase the potential for heat- related illnesses, particularly for those working or participating in outdoor activities,” according to the NWS.
A less-severe heat advisory was in effect in the San Fernando Valley, forecasting high temperatures in the 90s to 105.
“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,” NWS forecasters advised. “Young children and pets should never be left unattended in vehicles under any circumstances.”
The Los Angeles County Department of Public Health issued an extreme heat warning that will be in effect through June 29 in the Santa Clarita and Antelope valleys, and in the western San Fernando
Valley. A heat alert will be in effect from June 29 in the eastern San Fernando and San Gabriel valleys, and the Los Angeles Basin.
Health officials urged residents to stay hydrated, wear sunscreen and lightweight clothing, beware of symptoms of heat stroke and check on vulnerable friends and relatives, such as the sick, older adults, pregnant women, children and those who live alone.
Los Angeles County library officials announced that the Lancaster Library, Quartz Hill Library and Acton Agua Dulce Library would be open until 10 p.m. June 28 to serve as cooling centers.
The California Independent System Operator (ISO), which runs the power grid, issued a heat bulletin June 27 in anticipation of increased electricity demand due to above normal temperatures across California—and warned of a possible flex alert. But later the agency said there were no such plans because “projected resource deficiencies [were] addressed in the day-ahead market; there are now sufficient supplies to meet expected demand.”
But the agency also said it’s continuing to monitor weather conditions and is asking Californians to stay prepared.
If weather or system conditions worsen, the ISO may notify the public about potential energy shortages and the need to conserve. The ISO could also issue a flex alert, a voluntary call for consumers to reduce electricity use during critical times of stress on the grid.