National Weather Service Red Flag Warning Includes Diamond Bar and Walnut

By City News Service

Moderate to strong Santa Ana winds, very low relative humidity and dry fuels will put large portions of the Southland under a Red Flag warning at the start of the week, National Weather Service officials said Saturday.

The critical fire weather warning will be effective in some areas from Sunday night through Wednesday and from early Monday morning through Wednesday in others, according to the Weather Service.

"Strong surface high pressure will build across the Great Basin Sunday night through Tuesday, bringing increased offshore flow across Southern California," according to a Weather Service statement.

Northeast winds were forecast to increase rapidly late Sunday evening across the mountain areas before spreading into valleys and coastal zones overnight into the early morning hours of Monday, according to the NWS, which reports that the winds, gusting as high as 60 mph in mountain areas, are expected to continue into Wednesday.

The windy conditions will be accompanied by relative humidity between 10 and 15 percent on Monday and in the single digits on Tuesday and Wednesday, bringing "critical fire weather conditions" that are expected to last into Wednesday, according to the NWS.

"If fire ignition occurs, there could be rapid spread of wildfire that would lead to a threat to life and property," according to the Weather Service.

Temperatures will warm into the upper 70s on Monday and into the lower 80s on Tuesday and Wednesday in the Los Angeles and San Gabriel Valley areas, the Weather Service reported.

A Cal Fire official said additional personnel and equipment would be deployed during the enhanced wildfire threat in the agency's southern region, which includes Los Angeles, Orange, Riverside and San Diego counties.

The Los Angeles city and county fire departments were also planning enhanced deployments in some areas, as was the Orange County Fire Authority, officials said.