The heat wave that brought sweltering conditions to San Diego County is expected to peak Friday with temperatures 5 to 10 degrees above average.
A National Weather Service heat advisory is set to take effect in San Diego County at noon and extend until 6 p.m.
Highs of 83 to 88 degrees are forecast Friday for the coast, 92 to 97 degrees in inland areas, 96 to 101 in the western valleys, 93 to 98 near the foothills and around 109 degrees in the deserts. Forecasters predicted highs of 91 to 97 in the mountains, but with a slight chance of afternoon showers and thunderstorms.
"High pressure aloft will bring hot weather to portions of extreme Southwest California today with temperatures a few degrees warmer than on Thursday, according to the weather service. "This will bring excessive heat to portions of extreme Southwest California today, mainly in the valleys, inland coastal areas, mountains below 4,500 feet and portions of the northern Coachella Valley near Palm Springs."
Forecasters urged people to protect themselves and their loved ones against dehydration, heat stroke and other heat-related illnesses. Residents were advised to stay well-hydrated, avoid working in the sun, check on neighbors and relatives — especially the elderly — and provide plenty of water to pets and livestock.
Authorities also warned against leaving children, senior citizens or pets in parked cars, which can quickly become death traps in high heat.
Anyone seeking a place to beat the heat can visit any of the several cooling centers scattered throughout the county. The centers are generally libraries, senior centers and community centers that provide air- conditioned shelter while in operation, and are marked with a Polar Bear Cool Zone logo. A full list of locations is available online at coolzones.org.
Cooler temperatures are expected to prevail this weekend.
