The National Weather Service in Sacramento has upgraded the Winter Storm Watch to a Winter Storm Warning for the West Slope Northern Sierra Nevada and Western Plumas County,

As much as 48 inches of snow could fall in the hardest-hit areas, with people told not to travel during the worst of the storm.

As weekend storms bear down on Southern California, forecasters are beginning to pinpoint when the most rain will fall and how much the region is likely to get. “We will get rain, but we won’t get it on Friday,

The storm will roll in Friday evening, gather strength overnight, and reach its snowy peak from Saturday night into Sunday when the heaviest flakes are expected.

On Wednesday at 2:50 p.m. a winter storm watch was issued by the NWS Hanford CA valid from Friday 5 p.m. until Sunday 11 p.m. The watch is for Yosemite, Upper San Joaquin River, Kaiser to Rodgers Ridge,

Storm systems are expected to arrive in Southern California this weekend, bringing widespread rain and possible thunderstorms. The first storm will arrive late Friday night as some parts of Southern California may experience some moisture Friday night into early Saturday before steadier rain hits the region,

A strong spring storm will blanket the Sierra with a heavy snowfall, making travel difficult.

"Mountain travel may be very difficult to impossible," the National Weather Service warned.