Skies are expected to clear up today in the Bay Area, but it won’t last long, NWS says

A second, more powerful storm to bring more rain

The dusting of snow on some Bay Area mountaintops Thursday morning signaled what was in store for Thanksgiving — after the rain, the cold.

The cold front that brought the Bay Area’s first significant rain this season earlier in the week plunged the mercury into the 30s in many places Thursday morning.

Bay Area forecasts for today predict dry conditions but cold temperatures — staying at or below the low 50s in most areas, according to the National Weather Service. Cities such as Livermore, Walnut Creek, San Ramon and San Jose were expected to see temperatures drop to the low to middle 30s overnight.

A frost advisory will be in effect overnight to 9 a.m. today in parts of the South and East Bay, and a freeze warning for much of the North Bay.

The cold temperatures can kill outdoor plants and pose a threat to pipes and unsheltered pets or livestock.

The weather service reported snow falling above 2,500 feet Wednesday night and Thursday morning. Temperatures fell to 29 degrees overnight atop Mount Umunhum at 3,488 feet overnight and rain mixed with snow at the 1,800-foot Highway 17 summit.

Interstate 5 through Grapevine in Southern California was closed for more than five hours on Thursday morning because of snow covering the roadway. Officials were diverting drivers to US-101 until it reopened about 2 p.m. Thursday.

Oakland saw hai l Wednesday evening as temperatures dipped into the low 40s. Santa Cruz saw some showers and small hail Thursday afternoon, according to the weather service.

Skies are expected to clear up by today, but it won’t last long.

The second and more powerful storm to hit Northern California this week is expected to deliver widespread rain over the weekend. It should roll through most of Central and Northern California from Saturday afternoon through Monday afternoon, with the heaviest downpours expected in the Santa Cruz Mountains and along the Big Sur coast, according to the weather service.

Estimated rainfall totals for the Bay Area include up to 5 inches in the Santa Cruz Mountains, up to 8 inches along the Big Sur Coast and up to 2 inches in San Jose and the East Bay. Gale warnings have been issued ahead of high wind gusts expected from Saturday morning to Sunday morning in the San Fransisco Bay and off the coast from Point Reyes to Pigeon Point.

Although the strongest rainfall will occur over the weekend, a chance of showers will continue until Wednesday, according to the weather service.

“We started off the season fairly dry, so we have a ton of room to make up and do welcome this rain,” said Carolina Walbrun, a meteorologist at the weather service.

The weekend storm clouds will act as an “insulated blanket,” raising the low overnight temperatures to the high 40s, Walbrun said.

The upcoming rainfall comes on the heels of this week’s earlier storm, which was the largest to hit Bay Area in six months.

Rainfall totals reported Wednesday evening included 1.14 inches at the Calero Reservoir near San Jose, 1.03 inches at Richmond City Hall and 1 inch at Interstate 880 and Auto Mall Parkway in Fremont.