Southern California suffered the worst day yet of a lingering heat wave Tuesday, with temperature records set amid a statewide Flex Alert and the prospect of rolling power blackouts.
Temperatures neared 100 degrees around downtown Los Angeles on Tuesday, while farther north, the mercury reached 110 in Lancaster, 109 in Santa Clarita, 106 in North Hollywood and 105 in Pasadena.
In Orange County, records were set for this date in Anaheim at 105 degrees, breaking the old record of 101 in 1992, and Santa Ana at 106 degrees, breaking the old record of 95 in 2010, according to the National Weather Service.
Forecasters warned that excessive heat and a heightened risk of wildfires would last at least through Thursday.
An excessive heat warning, which has been extended since it was first issued last week, will be in force until 9 p.m. Thursday in the San Fernando, Santa Clarita, San Gabriel and Antelope valleys, as well as the San Gabriel and Santa Monica mountains. The National Weather Service said conditions in those areas would be “dangerously hot.”
In inland Orange County and the Santa Ana Mountains, the warning was in effect until 10 p.m. Thursday.
A less serious heat advisory was in effect until 9 p.m. Thursday in the L.A. coastal zone — beach cities, metropolitan Los Angeles, Downtown L.A. and the Hollywood Hills.
“Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities,” according to he NWS. “Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening.”
The NWS added that “very hot conditions will continue through the week with very warm nights, especially for valley and interior areas,” according to the NWS. “Temperatures will cool only slightly later in the week and will remain above normal through early next week. There is a slight chance of thunderstorms through Wednesday mostly over the mountains and the Antelope Valley.”
The heat wave is being caused by a strong ridge of high pressure anchored over Nevada, forecasters said.
Residents were being urged again Tuesday to conserve energy wherever possible to avoid strain on the power grid and possible rolling blackouts.
A statewide Flex Alert issued by the California Independent System Operator, which manages the state power grid, will be in effect from 3 to 10 p.m. Tuesday and Wednesday, with conservation considered especially critical during those hours.
Residents are being asked to use air conditioning early in the day and set thermostats at 78 in the afternoon and evening hours, while avoiding the use of major appliances during the Flex Alert hours.
Cal-ISO officials told reporters rolling blackouts could again be implemented Tuesday evening, but they might be avoided if residents repeat the level of conservation seen Monday, when power outages were avoided.
The excessive heat has led to stress on the state’s electrical grid over recent days, prompting some rolling blackouts Friday and Saturday night for the first time since 2001.
Along with torrid weather, the NWS forecast “elevated fire danger.” The NWS has not issued any red flag warnings because winds have not been strong enough to meet NWS criteria, according to forecasters.