Strong Santa Ana winds, very dry air and low humidity will combine Monday to confront the southland with a high risk of wildfires, according to the National Weather Service.
Most of L.A. County is at risk. Red flag warnings denoting a high risk of wildfires will be in effect in the San Gabriel Mountains, the Angeles National Forest, the Santa Monica Mountains Recreational Area, the San Fernando, Santa Clarita and San Gabriel valleys, and the L.A. coastal zone, which consists of beach cities, metropolitan L.A including the downtown area, and the Hollywood Hills. No warning was in effect in the Antelope Valley.
The mountains will be swept by northeast winds of between 25 and 45 miles per hour, gusting to 65 mph and, at times, 75 mph, according to NWS forecasters. At the same time, humidity levels will be down to between 4 and 12 percent, they said. A red flag warning went into effect in the mountains at 10 Sunday night and is scheduled to be in force through 8 p.m. Tuesday.
“If fire ignition occurs, conditions are favorable for extreme fire behavior, which would threaten life and property,” warned a statement issued by the NWS in Oxnard.
Amid humidity levels of 4 to 12 percent, northeast winds of 20-35 mph with gusts of 55 mph are expected in the San Fernando and Santa Clarita valleys, along with isolated 65-mph gusts in the hills, according to the NWS. The red flag warning in those areas will be in effect from 3 a.m. Monday to 8 p.m. Tuesday.
Also in effect from 3 a.m. Monday to 8 p.m. Tuesday is a red flag warning in the San Gabriel Valley and the L.A. coastal zone. Winds of 15-30 mph are forecast for the hills and canyons of those areas, along with 45-mph gusts, amid humidity levels of 4-12 percent.
In Orange County — including mountain areas below 6,000 feet, the Cleveland National Forest and in valley areas — winds of 20-40 mph with 60 mph gusts are expected, gusting to 80 mph in some areas amid 5-10 percent humidity. The red flag warning in Orange County will last from 3 a.m. Monday until 8 p.m. Tuesday.
“A combination of strong winds, low relative humidity and warm temperatures can contribute to extreme fire behavior,” warned the NWS station in San Diego, which monitors Orange County conditions.
High wind warnings denoting winds or gusts of at least 58 mph will be in effect wherever red flag warnings have been issued, including in Ventura County and points north, and temperatures will be in the mid 80s.
“Winds this strong may down trees and power lines, causing property damage or power outages. Cross winds can make driving difficult, especially for drivers of high profile vehicles and vehicles towing trailers,” warned an NWS statement.
Strong wind gusts were recorded in L.A. County after 1 Monday morning. The strongest were in the San Gabriel Mountains, including 54 mph at Warm Springs and 49 mph in Chilao, but strong gusts were recorded elsewhere as well: 43 mph in Chatsworth, 41 mph in Saugus, 38 mph in Glendale, 36 mph in Santa Clarita and 35 mph in Malibu.
Strong winds were also recorded in Orange County overnight, both in the mountains and at low elevations, including 68 mph in Fremont Canyon, 58 mph in Mission Viejo, 53 in Portola Hills, 52 mph in Tustin, 37 mph in Lake Forest, and 30 mph in Yorba Linda and at John Wayne Airport, 26 mph in Costa mesa and 25 mph in Garden Grove and Santa Ana, according to the NWS.
The NWS forecast sunny skies Monday and highs of 64 degrees on Mount Wilson; 69 in Palmdale; 70 in Lancaster; 79 in Saugus; 81 in Avalon and San Gabriel; 83 in Pasadena and Woodland Hills; 85 in Burbank; and 87 in Downtown L.A., Long Beach and at LAX. Temperatures will reach the low 90s in Woodland Hills starting Tuesday but will slip to the low 80s and high 70s in other L.A. County communities.
The NWS issued a forecast of windy for Orange County Monday, along with highs of 77 in San Clemente; 80 in Yorba Linda; 81 in Laguna Beach, Anaheim, Irvine and Mission Viejo; 82 in Newport Beach; and 83 in Fullerton. Orange County temperatures will stay at roughly the same level for several days.