SAN DIEGO -- Arid Santa Ana winds and record-breaking heat are in San Diego County's forecast for the second straight day Tuesday, a day after Ramona, Vista, Alpine and El Cajon shattered old heat records, according to the National Weather Service.
The torrid conditions have San Diego area firefighters on high alert for wildland brush fires and will force several dozens of schools to shut down early again Tuesday as temperatures are forecast to hit 20 to 25 degrees above averages.
All advisories that were in effect Monday remained in effect Tuesday, including a red flag fire warning for the inland valleys and mountains that's set to expire at 6 p.m. Wednesday; an excessive heat warning for most of the county west of the mountains that's set to expire at 8 p.m. Tuesday evening; and a wind advisory for the mountains and valleys set to expire 2 p.m. Wednesday.
The U.S. Forest Service increased the threat index Tuesday for Santa Ana-driven wildfires. On Monday, the agency said any fires that erupted "may grow rapidly." Tuesday, the Forest Service said that "upon ignition, fires will grow rapidly and will be difficult to control."
The red flag warning that will expire Wednesday went into effect Sunday, a day after the 10th anniversary of the start of the catastrophic Harris and Witch Creek fires, conflagrations that spread over a total of about 288,400 acres, destroyed more than 1,300 homes and killed seven people.
Wednesday will be the 14th anniversary of the start of the Cedar Fire, which killed 15 people and destroyed more than 2,230 homes while charring about 280,000 acres.
Fire agencies across the region, including Cal Fire and the San Diego Fire-Rescue Department, have beefed up staffing to help deal with any possible blazes that erupt. Meanwhile, about 85 schools have announced a second straight day Tuesday of minimum-day schedules to beat the heat.
Several cities set new heat records Monday, the NWS said, with afternoon highs of 104 degrees in El Cajon, beating the prior Oct. 23 milestone of 100, set in 2003; 101 in Ramona, (97 degrees, 2003); 100 in Vista (99, 1965); and 99 in Alpine (98, 1959).
El Cajon is expected to hit 105 degrees Tuesday, which would shatter the previous Oct. 24 record of 98 set in 2007. Chula Vista, Ramona and Vista are also expected to hit triple digits and set new heat records Tuesday, while forecast highs of 98 in Alpine and 96 in San Diego would also set new high- temperature records for Oct. 24.
As for the fire danger, the red-flag warning that was initially supposed to end Tuesday has been extended to 6 p.m. Wednesday as models showed high winds were expected to continue for another day. Forecasters expect Santa Ana winds gusts as high as 60 mph at times in locales and air-moisture levels dipping into the single digits over the period.