A storm out of the Gulf of Alaska invaded the Southland Wednesday and will unleash rain, snow, and cold winds through Thanksgiving while causing rough seas and wreaking havoc on the region’s roads, forecasters said.
National Weather Service meteorologists forecast between 1 and 2 inches of rain along the coast and in valleys, 2 to 4 inches in the mountains and foothills, 6 to 12 inches of snow in most mountain locations but between 12 and 24 inches in the San Gabriel Mountains.
They warned of “significant holiday travel delays and road closures, major snow impacts, roadway flooding at lower elevations, significant flight delays, possible flash floods and debris flows over recent burn areas, and Hazardous road conditions.
A winter storm warning signifying an expectation of difficult travel conditions will be in effect for Los Angeles County mountains until 4 a.m. Friday.
Most mountain areas will get 6 to 12 inches of snow — including 3-6 inches in the Grapevine, where California Highway Patrol officers escorted traffic Wednesday morning — with up to 24 inches of snow expected to accumulate at higher elevations in the San Gabriel Mountains.
The snow level will drop to 2,500-3,000 feet tonight, according to the weather service.
“Travel could be very difficult to impossible,” warned an weather service statement. “The hazardous conditions could result in temporary road closures.”
The snow became disruptive apparently earlier than was expected. Shortly after 8 a.m., Caltrans announced that a section of state Route 2 has been closed from state Route 39 to “2.3 miles west of Big Pines” in the Angeles National Forest due to snow.
A winter storm warning will be in effect until 4 p.m. Thursday in the Santa Ana Mountains, which spread across some of Orange County.
“A Winter Storm Warning for snow means severe winter weather conditions are expected. If you must travel, keep an extra flashlight, food and water in your vehicle in case of an emergency,” urged the weather service.
Also in force in Orange County — both inland and coastal areas — is a flash flood watch, from late Wednesday evening through Thursday night.
Total snowfall accumulations of 3 to 6 inches are expected between 4,000 and 4,500 feet, 6 to 18 inches from 4,500 to 5,500 feet, and from 1 to 3 feet above 5,500 feet, said the weather service. Snowfall at lower elevations below 4,000 feet will be of 1 to 3 inches, mostly late Thursday through Friday.
Weather service forecasters said a deep, cold upper-level trof will continue to bring scattered showers and mountain snow showers overnight. Additional rainfall and mountain snow is expected on Thanksgiving as the low pressure system remains in the area.
Rainfall totals in Los Angeles County included 0.82 of an inch in Beverly Hills, 0.76 of an inch in Claremont, 0.75 of an inch in Newhall, 0.73 of an inch in Agoura Hills, 0.71 of an inch in La Verne, 0.66 in Woodland Hills, 0.61 of an inch in La Canada Flintridge, 0.54 of an inch in Alhambra, Burbank and Van Nuys, 0.47 of an inch in Pomona, 0.43 of an inch in Cangoa Park and Lancaster, 0.41 in downtown Los Angeles and Saugus, and 0.38 of an inch in Sanberg.
The rainfall totals in Lancaster and Sanberg were both records for the day. The previous record in Lancaster was 0.39 of an inch in 1981. The previous record in Sandberg was 0.07 of an inch set in 1971.
Orange County rainfall totals included 0.59 of an inch in Corona Del Mar, 0.57 of an inch in Laguna Hills, 0.52 of an inch in Brea and Lake Forest, 0.48 of an inch at John Wayne Airport, 0.46 of an inch in Yorba Linda, and 0.44 of an inch at Costa Mesa and Coto de Caza.
Los Angeles County high temperatures included 34 at Mount Wilson, 48 in Palmdale and Lancaster; 52 in Saugus and San Gabriel; 55 in Pasadena; 53 in Burbank; 56 in Woodland Hills, 58 in Avalon, downtown Los Angeles and Long Beach; and 59 at Los Angeles International Airport.
Orange County highs included 57 in Yorba Linda; 55 in Lake Forest; 58 in Huntington Beach; 59 in Anaheim, Fullerton, Newport Beach and Santa Ana; 61 in Laguna Beach and 62 in John Wayne Airport.