A red flag warning denoting a high risk of wildfire will go into its third day today in the San Gabriel Mountains and the Antelope Valley, and forecasters said the Santa Clarita Valley and Santa Monica Mountains would be threatened as well.
The red flag warning, targeting the San Gabriels in both Los Angeles and Ventura counties and foothill areas in the Antelope Valley, was issued Monday and is scheduled to expire at 9 p.m. Thursday. Forecasters say it was prompted by high heat, very low humidity, bone-dry vegetation and strong onshore winds.
The red flag warning in the San Gabriels also applies to the Angeles National Forest in Los Angeles County and the Los Padres National Forest in Ventura County.
The Santa Clarita Valley and the Santa Monica Mountains in Los Angeles County and the Carrizo plain in southeastern San Luis Obispo County will also experience red flag conditions, but for only between two and four hours a day, “which is just under the duration criteria for a (red flag) warning but still very concerning,” according to an NWS statement.
The humidity level in the San Gabriels and the Antelope Valley is reported to have dipped to an uncommonly low 2 percent during daytime hours and to have climbed to no more than 20 percent at night.
The humidity situation is expected to improve by Friday and the wind should weaken, “and while elevated fire weather concerns will exist, it should not be heightened enough for a red flag warning,” it said.
In the meantime, southwest winds of between 15 and 25 miles per hour, with gusts of between 30 and 40 mph, will continue to buffet the San Gabriel Mountains, mainly in the afternoon and evening, according to the NWS.
Winds of between 15 and 30 mph, gusting to 50 mph, will sweep the foothills in the Antelope Valley in the afternoon and evening but fall to between 8 and 15 mph with 25-mph gusts overnight and in the morning hours, it said.
If a fire starts, “conditions are favorable for extreme fire behavior and rapid spread of wildfire, which would threaten life and property.”
The NWS forecast sunny skies today and slightly lower highs than Tuesday in some communities: 74 at LAX; 84 in Avalon and downtown Los Angeles; 87 in Long Beach; 92 on Mount Wilson; 93 in San Gabriel; 97 in Burbank; 98 in Pasadena and Palmdale; 99 in Lancaster; 100 in Saugus; and 102 in Woodland Hills.
Highs will fall by another 3 or 4 degrees Thursday, then drop to a slightly lower level through Tuesday. Woodland Hills, for example, will drop to 98 Thursday and Friday, 93 Saturday, and 95 for the following three days.
Forecasters said they consider today to be the last day of the region’s heat wave, which began Saturday.
