Strong gusty winds blew across the Southland today, setting the stage for what the National Weather Service calls the “first significant Santa Ana wind event” of the season beginning this evening — a development that raises the danger of wildfire and could make driving difficult.
In an indication that the perceived severity of the threat has increased as a result of high winds and low humidity, the National Weather Service this morning issued a red flag warning for the San Gabriel Mountains in Los Angeles and Ventura counties, the Angeles National Forest in Los Angeles County and Ventura County’s Los Padres National Forest. It will be in effect from late tonight until Friday afternoon.
“Other portions of Los Angeles and Ventura counties will likely see brief critical fire weather conditions on Friday,” an NWS statement said. “The northeast winds are expected to be weaker on Friday night and Saturday, but very warm and dry conditions will continue.”
Since last night, northerly winds have been sweeping parts of Santa Barbara County and points south, with winds of 20 to 35 miles per hour accompanied by gusts of between 45 and 55 mph lashing parts of the Southland, including the Interstate 5 corridor in the San Gabriel Mountains.
In Los Angeles County, the National Weather Service reported gusts overnight of 51 mph at Whitaker Peak in the San Gabriels, 38 mph at Poppy Park in the Antelope Valley, and 36 mph in the Santa Clarita and San Fernando valleys.
Reflecting conditions, the National Weather Service extended some weather advisories that were scheduled to expire this morning.
A wind advisory was scheduled to be in effect until noon Friday in L.A.’s coastal zone — the seaside, metropolitan Los Angeles, downtown and the Hollywood Hills — as well as the San Fernando and Santa Clarita valleys.
In L.A. County mountains — both the San Gabriels and Santa Monicas — a wind advisory will be in effect until 9 tonight and a more serious high wind watch, which reflects an expectation of 58-mph gusts or greater, will be in force until Friday morning.
“The first significant Santa Ana wind event of the season will kick in by Thursday evening …,” an NWS statement said, adding that forecasters expect 60-mph gusts in the mountains and that a high wind watch, will go into effect in the San Gabriels tonight, lasting until Friday morning. Slightly tamer winds — 20-30 mph with 40-50-mph gusts — are expected tonight in valley areas, coastal cities like Malibu, and the Hollywood Hills.
Forecasters said gusty winds would make driving difficult, especially for drivers in high-profile vehicles on Interstate 5, the Antelope Valley (14) Freeway, Interstate 405 (the San Diego Freeway), and highways 23, 101 and 118.
“The potentially strong winds Thursday night into Friday morning may down trees and power lines and cause property damage,” a statement said. “When driving, use extra caution. Be prepared for sudden gusty cross winds.”
The wind also will increase the danger of wildfire, especially as the humidity level will fall below 20 percent tonight, NWS forecasters said.
The NWS’s Santa Ana wind season lasts from September until February.
A risk of coastal flooding also persists in the Southland through today because of a combination of high surf and unusually high tides.
The highest high tides are expected during the mid to late morning hours, an NWS statement said, adding that water levels are expected to range from 7 to 7.5 feet.
“There will be a risk of coastal flooding during this time as elevated water levels result from the combination of building surf, and unusually high tides,” the statement said, specifically citing Long Beach in L.A. County, Port Hueneme in Ventura County and Pismo and Oceano beaches in San Luis Obispo County as locations prone to coastal flooding.
A coastal flood advisory will be in effect until 2 p.m. in Los Angeles County and 9 p.m. in Orange County. Coastal flood advisories also will be in force in Ventura, Santa Barbara, San Luis Obispo, and San Diego counties.
The NWS also forecast a long-period northwest swell today through today, with a potential for high surf on west- to northwest-facing beaches. Forecasters said the expected conditions could generate flooding of such low- lying areas as beach parking lots, adjacent streets and, possibly, structures.
Along with wind and the surf, the NWS forecast sunny skies today and highs of 72 on Mount Wilson; 74 in Palmdale and San Clemente; 75 in Lancaster; 76 in Saugus; 77 in Newport Beach; 78 in Avalon and Laguna Beach; 79 in Mission Viejo; 80 at LAX; 81 in Irvine; 82 in Anaheim and Fullerton; 83 in Long Beach, Yorba Linda and downtown L.A.; 84 in Pasadena, San Gabriel and Burbank; and 85 in Woodland Hills. Friday’s temperatures will be a few degrees higher.
