Sea Breeze Drops Mercury but Fire Danger Still High

With on-shore breezes replacing dry Santa Ana winds, the Thanksgiving holiday in Orange County is shaping up with warm but pleasant temperatures. Even so, Anaheim was one of the nation’s hot spots Monday.

“After the last three days of dry hot Santa Ana winds, we’re definitely in for some cooling temperatures,” said Rick Dittmann, a meteorologist with WeatherData Inc., which does forecasts for The Times.

Temperatures are expected to dip for the rest of the week, including Thanksgiving Day, when a cooling trend is expected to bring highs in the 70s and 80s for inland county areas. Along the coast, where morning low clouds are expected, highs will range in the upper 60s.

On Monday, Anaheim posted a high of 89 degrees, behind Northridge, with 91 degrees, and Glendale with 90, the National Weather Service reported. Orange County’s record high for a Nov. 20 was a 91 in 1917 in Santa Ana, according to local historian Jim Sleeper.

Dittmann said the change in temperatures was most evident on Monday between noon and 1 p.m. Temperatures rose quickly in the morning hours, bringing the mercury to 85 degrees in Santa Ana by 1 p.m. But then they dropped quickly because of on-shore breezes, he said.

Threatening clouds that hung over most of Orange County late Monday were from an upper-level, low-pressure system rotating from Baja California. The disturbance brought slight drizzles in the San Bernardino-Riverside area and some relief to firefighters who are expected to contain an 835-acre blaze by 6 a.m. today.

Sue O’Donnell, a state Department of Forestry spokeswoman, said the cooler temperatures Monday afternoon were welcomed by many of the 250 firefighters who were fearful of another day of bone-dry desert winds that had pushed the blaze toward the Corona-Norco area.

“Believe me, we’re thankful it’s cooling down and also the fact that we haven’t had that many winds,” O’Donnell said.

Relative humidity, which is an indication of the amount of moisture in the air, dropped radically to just 5% to 10% on Sunday in the Riverside area, she said. By Monday evening it had risen to 45%, which prompted fire officials to predict the fire’s containment by this morning, with full control expected by 6 p.m. tonight.

A firefighter and four hand-crew members were injured in the brush fire, none seriously. One outbuilding and the wood shake roof of a residence south of Pedley were damaged in the blaze.

Cooler temperatures do not decrease Orange County’s present tinderbox fire conditions, which remain extremely dangerous, said Capt. Henry Raymond, a spokesman for the Orange County Fire Department.

“Just because there’s a change in the weather system doesn’t mean that there’s an overnight drop in our critical situation here in Orange County,” Raymond said.

County fire officials use a formula involving humidity and the amount fuel moisture in the brush to determine fire hazard conditions, he said.

“We believe it’s real important to educate the public right now, because with the Thanksgiving holiday and cooler temperatures, people will want to crank up their fireplaces,” Raymond said.

He urged residents to check their chimney screens, spark arresters and flues.