Southern California will be in fire danger from hot, dry weather for much of the week, with strong Santa Ana winds coursing over mountains and foothills through Monday afternoon, then weakening but lingering through the week, bringing triple-digit temperatures for several areas, forecasters said Sunday.
A red-flag fire danger warning was issued to start at 5 a.m. Monday through the early evening for Riverside and San Bernardino county mountains, as well as the Santa Clarita Valley in Los Angeles County and Los Angeles County mountains, excluding the coastal Santa Monica Mountains, the National Weather Service said.
Those areas were under fire weather watch until the red-flag warnings kick in.
Firefighters at the Bobcat fire in the Angeles National Forest and the El Dorado fire in the San Bernardino National Forest were preparing for the siege.
In Los Angeles County, fire dangers will be “elevated to brief critical fire weather conditions Tuesday through Friday for areas away from the coast, including an increased threat of plume-dominated fires with extreme fire behavior at times,” the National Weather Service said.
— NWS San Diego (@NWSSanDiego) September 27, 2020
Winds along the 5 Freeway north of the Santa Clarita Valley were already shifting into the characteristic Santa Ana direction from the northeast, with gusts between 25 mph and 35 mph on Sunday, the NWS said.
The watches for Riverside and San Bernardino are for the mountains and valleys. The Santa Ana winds, blowing from the desert towards the ocean, are forecast to be strongest through Monday afternoon at 15 mph to 25 mph and gusting to 40 mph. Daytime humidity is expected at 10 to 15%. That all amounts to critical fire weather conditions on Monday, the NWS said.
Firefighters at the El Dorado fire in the San Bernardino National Forest on Sunday were working to deepen fire lines in the northern edge of the blaze, Plans Section Chief Bob Evans said in a Sunday briefing.
.”We’ve been trying really hard to put a lot of effort into this, because we got a wind shift later through the night, so our fire lines will be challenged by a northeast and east wind,” he said in reference to the Santa Anas. The fire, burning since Sept. 5, was 92% contained with 22,666 acres burned.
At the Bobcat fire burning in the Angeles National Forest, “We are taking all resources on the incident to prepare for the wind event,” Kerri Gilliland of the fire interagency management team said Sunday. That included looking for hotspots to extinguish along the edge of the fire.
The Bobcat fire was 65% contained at 114,103 acres. It started Sept. 6.
— NWS Storm Prediction Center (@NWSSPC) September 27, 2020
The heat and wind are being generated by a high-pressure system over Western states, and the conditions are expected to continue through Thursday, with slight cooling, but temperatures are expected to stay above normal through the weekend.
The hottest temperatures, topping 100 in several places away from the coast, are expected Tuesday through at least Thursday. A heat advisory was put in place by the NWS for Tuesday morning to Thursday night for the inland areas of Orange County as well as valleys in Riverside and San Bernardino counties.
Some highs forecast for Monday include 93 degrees for downtown Los Angeles; 99 for Woodland Hills; 95 for Pasadena; 94 in San Gabriel; 81 in Long Beach, 95 in Ontario; 99 in Riverside; 100 in San Bernardino; 88 in Santa Ana, and 75 in Newport Beach.
Source: Orange County Register