Californians braced for a weekend of major winter storms that was expected to bring strong winds and rain along the coast and heavy snow in the Sierra Nevada (search).

"The entire state of California is pretty much under the gun for the next three or four days," Duane Dykema, a forecaster with the National Weather Service (search) in Monterey, said Thursday. "People are definitely going to have to be wary if they have travel plans, especially if they plan to go to the mountains."

The first storm, which originated in the eastern Pacific Ocean, began to reach the San Francisco Bay area late Thursday night. The NWS issued a high wind watch for the region between San Francisco and Monterey and light rain began falling in the South Bay.

Eric Lamoureaux, a spokesman for the Governor's Office of Emergency Services, said operations centers in Sacramento and Orange County have been activated and would be staffed around the clock through Sunday. The agency was prepared to deploy resources to hard hit areas.

"I want to encourage all Californians to make sure they are prepared for these severe storms that are targeting the state this weekend," OES Director Henry Renteria said. "We are taking steps to make sure the state is prepared to respond to any weather-related incidents that may develop and we need citizens to be ready as well."

OES said the storm is a good reminder for people to update their emergency kits, which should include battery-operated flashlights and radios.

The U.S. Coast Guard (search) advised Bay Area boaters and beach visitors to "exercise extreme caution" over the next four days, warning of waves that could reach 17 feet high and winds up to 20 knots per hour. It also issued a gale-force wind and high surf advisory for Monterey Bay and the Central California coast.

California's north coast could see some wind and rain, but the brunt of the storm was expected to hit the Bay Area and then head south to the Los Angeles area by late Friday morning.

A second storm, which originated in Western Canada, was forecast to move south through Washington and Oregon before reaching California on Friday night, offering no break between the storms.

"It's going to bring a lot of moisture and storminess throughout California," Dykema said.

The two storms could cause flooding near streams and rivers, produce damaging winds and disrupt air travel, Dykema said. Dry weather was not anticipated until the middle of next week, he said.

Over the next four days, the Bay Area is expected to see between 1 and 3 inches of rain at low elevations, and 2 to 5 inches in the coastal mountains.

Southern California is expected to receive between 4 and 8 inches of rain in coastal and valley regions and up to 20 inches in the mountains.

Between 3 and 5 feet of snow is expected in the Sierras, where a winter storm warning has been issued from 4 a.m. Friday to 4 p.m. Sunday.

A continuous band of storms that began on Dec. 27 brought up to 9 feet of snow at some ski resorts around Lake Tahoe and pushed rainfall totals throughout California well above normal.

Since July 1, the start of the rainfall season, Los Angeles has received 15.68 inches of rain — nearly four times the usual rainfall for the period, and more than the city normally gets in a year. San Francisco has received 14.23 inches of rain since July 1, about 165 percent of normal.