On Wednesday, high temperatures of 99 degrees in Chula Vista and 97 in Vista topped previous records for a Sept. 9 of 91 and 96 degrees, respectively, both set in 1990. A high of 92 degrees in Chula Vista on Tuesday also set a record, according to the National Weather Service.
Additionally, automated gauges in several locales in the valleys and mountains collected one to four-tenths of an inch of rain. In Rincon Springs near Valley Center, .66 inches of rain was recorded, according to the National Weather Service.
A National Weather Service heat advisory for coastal areas and the valleys is set to remain in effect until 6 p.m. A flash flood watch for all areas other than the coast will also extend through this evening. A beach hazards statement resulting from high surf will expire Friday afternoon.
Forecasters said slightly less intense heat was expected today but again predicted temperatures would be 5 to 15 degrees above average as a high- pressure system remains over California, forecasters said.
Highs of 88 to 93 degrees are forecast Thursday for the coast, 94 to 99 degrees in inland areas, 95 to 100 in the western valleys, 89 to 94 near the foothills, 81 to 90 in the mountains and 94 to 99 degrees in the deserts.
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 or pets in parked cars, which can rapidly become death traps in high heat.
Showers and thunderstorms will also continue to swamp the region. The weather service pegged the chance of measurable precipitation at 20 percent along the coast and in the deserts, and 40 percent in the valleys and the mountains.
"It is another warm and muggy morning in the lower elevations where temperatures as of 3 a.m. were generally in the mid to upper 70s,'' according to the weather service.
Areas in and below recently burned areas will be particularly susceptible to heavy runoff and debris flows should strong thunderstorms develop nearby.
Along the beaches, waves and surf of 3 to 5 feet are expected with sets that could reach 6 feet north of Carlsbad. Strong longshore and rip currents are also expected.
Tonight, unusually high temperatures are expected due to cloud cover that is resulting in part from Tropical Storm Linda. A more meaningful cooling trend is expected to kick in Friday and accelerate over the weekend and through next workweek, forecasters said.