The alert by the California Independent System Operator asks residents to cut back their power use, especially during peak hours of 2 to 9 p.m. The alert was initially issued only for today, but Cal-ISO later extended it through Thursday.
"Electricity supplies statewide are expected to be tight because of high summer temperatures driving up demand, power plant outages and transmission line import capacity reductions,'' according to Cal-ISO. "Power imports may be limited today because of high temperatures in neighboring states.''
Cal-ISO officials said conservation is especially important in the late afternoon, when air-conditioning use tends to push electricity use to its highest point of the day.
The agency recommended that people conserve energy by setting thermostats at 78 or higher; using fans and closing drapes; turning off unnecessary lights and appliances; and using major appliances only in the morning or late evening.
According to the National Weather Service, temperatures are expected to reach 76 in San Diego, 82 at Camp Pendleton, 81 in Vista and 82 in Chula Vista.
For updates and more information, visit FlexAlert.org.
Extremely hot weather is expected again in the deserts of San Diego County as high pressure lingers over the region.
A National Weather Service heat advisory for the deserts is set to remain in effect until 8 p.m. High temperatures in the most desert areas are expected to be between 110 and 115 degrees Thursday, and temperatures could soar to up to 118 degrees in the Anza-Borrego Desert.
Slightly lower temperatures are expected Friday, forecasters said.
“Temperatures will be 5 to 10 degrees above normal,'' according to the weather service. “Temperatures will gradually cool off this weekend, with a chance of thunderstorms over the mountains and deserts.''
Forecasters advised those who live in or are visiting the deserts to avoid potentially serious ailments by staying hydrated and avoiding unnecessary outdoor labor. Authorities also warned against leaving children or pets in parked cars, which can quickly become death traps in high heat.