Winter storm barreling toward L.A. is expected to bring rain and snow

The area’s first winter storm of the new year is expected to unleash rain, gusty wind and mountain snow across Southern California, which could lead to road closures, including the Grapevine, forecasters said Wednesday.

The storm, which originated in the Gulf of Alaska, will hit Northern California first before moving south, with experts warning of a wet commute Thursday. The system is expected to bring about 24 hours of rain and cold temperatures, but by Friday, the region will dry out with a warming trend into the weekend.

After what has been a mostly dry January, the storm will move into the Sierra Nevada on Wednesday, and officials are urging against travel in the Northern California mountains because of heavy snow.

Coastal and valley areas are likely to get a quarter to three-quarters of an inch of rain. The lower mountains and foothills are expected to receive more — up to 1½ inches — according to the National Weather Service.

“It looks like there’s some good moisture with this system, so we’ll be getting some good rainfall amounts,” said Lisa Phillips, a weather service meteorologist in Oxnard. “Definitely more than just a sprinkle.”

The chilly storm will also drop snow levels. Elevations 5,500 feet and higher could see 4 to 8 inches of powder, while those 4,500 to 5,500 feet are expected to get 2 to 4 inches.

With significant snow expected in Southern California’s mountain areas, road closures for Angeles Crest Highway, Highway 33 and the Grapevine section of Interstate 5 are anticipated, Phillips said. Wind gusts of 30 to 50 mph are also anticipated, with mountain areas experiencing the strongest blasts, she said.

The fresh snowfall will be good news for the state’s plush snowpack, which provides about 30% of the annual water supply for the state. The spring and summer snowmelt feeds rivers and reservoirs and eventually is distributed to various water agencies for farm irrigation, landscaping and urban drinking supplies.

Forecasts are suggesting a chance of light rain early next week, but after a wet December, “January is looking like a dud,” said Bill Patzert, former climatologist at NASA’s Jet Propulsion Laboratory.

The National Oceanic and Atmospheric Administration’s outlook for Jan. 22-28 shows below-average precipitation for most of California, especially Southern California, while temperatures are expected to be above normal.

“We’re not expecting any other real concerns with this,” Phillips said of Thursday’s storm. “Sometimes with winter storms, we deal with problems in burn areas that’ll bring down dirt and mud. We’re not expecting heavy rainfall to expect that type of problem.”

Times staff writer Paul Duginski contributed to this report.