Wind gusts topped 90 mph Monday in some parts of the Sierra, a preview of a major change in the weather across California that will bring rain and snow across the state for Thanksgiving.

Southern California

A “ broad swath of precipitation ” is expected to blanket Los Angeles County and surrounding areas starting early Wednesday, said Kathy Hoxsie, a meteorologist with the National Weather Service in Oxnard. The heaviest rain and snow are predicted to fall on Wednesday from the morning to the afternoon. Lighter showers are forecast for Thursday and Friday and could extend into the weekend. Rainfall estimates for this week’s storm call for about 1 to 2 inches for the coast and valleys, and 1.5 to 3 inches for the foothills and at lower elevations of the mountains. A foot or more of snow is possible at higher elevations.


Snow levels are expected to plummet from 4,000 feet on Wednesday to about 2,500 feet by Thursday. This means the 5 Freeway over the Grapevine, along with Highway 14 and Highway 33, will likely see a significant dusting of powder — and with it, the seemingly inevitable traffic snarl, said David Sweet, also a meteorologist with the National Weather Service in Oxnard.

San Diego County

The storm will drop a foot or more of snow at the top of Palomar Mountain, nearly a foot on Mt. Laguna, and 4 to 6 inches between the 3,000-foot and 5,000-foot level, affecting Julian, Pine Valley and the Alpine area of Interstate 8, the National Weather Service said.

Some ski resorts in the San Bernardino Mountains could receive as much as 2 feet of snow.


“The snow is going to affect travel in all of the mountain passes in Southern California, including the Cajon Pass on Interstate 15,” said Samantha Connolly, a weather service forecaster.

San Diego County’s coastal area is expected to receive between 1 and 2.5 inches of rain, while areas east of Interstate 15 will receive 2 to 3 inches. Some areas just east of Interstate 5 also could get 3 inches, the weather service says.

The weather service says a winter storm watch will be in effect for the mountains above 3,000 feet from late Tuesday night through Friday evening, and a flash flood watch will be in effect for all areas west of the mountains.

Bay Area/Northern California


Rain is forecast to arrive on Tuesday afternoon and continue sporadically through Thursday, according to Steve Anderson, a meteorologist with the National Weather Service in San Francisco. Half an inch to an inch of rain is predicted in the Bay Area.

Sierra

The snowstorm will begin in earnest Tuesday and last through the holiday. Some parts of the Sierra could see 3 feet of snow by Thursday. Tuesday and Wednesday will be the most dangerous period, with snow tapering off by Friday.

“Travel could be very difficult to impossible,” the service said. “If you are traveling for the Thanksgiving holiday ... finish your travels by midday Tuesday.”


Dangerous winds in the Sierra toppled a semitrailer truck, downed power lines and closed a stretch of highway in Southern California on Monday ahead of a winter storm expected to bring up to 2 feet of snow to mountain tops around Lake Tahoe. U.S. Highway 6 was closed due to downed power lines south of Yosemite National Park near Bishop. A wind gust of 94 mph was reported Monday morning at Mammoth Lakes Airport.

The Associated Press contributed to this report. Robbins writes for the San Diego Union-Tribune.