Big chill sets in, but no precipitation expected

Even after a burst of hail fell on Berkeley and chilly winds and low temperatures gripped the Bay Area all day Monday, forecasters warned the worst is still yet to come.

Overnight lows in the Bay Area were expected to range from 20s in the valleys to mid-30s near the coast — setting the region up to break longheld records Tuesday. Inland areas, including Morgan Hill and Gilroy, should drop below freezing into the upper 20s, said Steve Anderson, a meteorologist with the National Weather Service.

“They could be the coldest temperatures we’ve seen this winter,” Anderson said. “And it’s going to stay cool for quite some time.”

A freeze warning is in effect for the Bay Area until 9 a.m. — the first time such an alert has been triggered this year, Anderson said.

Although the temperatures were expected to be frigid overnight throughout the region, there is no chance of precipitation across the region Tuesday — even in higher elevations, said another National Weather Service meteorologist, Will Pi. The system will be mostly clear with light winds, he said.

“The main story is that there is going to be cold temperatures,” Pi said. “Make sure you have all of the pets and plants inside.”

Daytime temperatures for the region should be in the 50s for the remainder of the week.

San Francisco has expanded capacities at homeless shelters in preparation for the cold. Transportation is being provided for those who choose to go, and street outreach workers are passing out extra blankets, officials said.

Up in the Santa Cruz Mountains, a dusting of snow was reported at elevations above 2,000 feet Monday. And in the Sierra, a fresh blanket of snow coated the peaks around Lake Tahoe. Some areas received up to 7 inches of snow — a welcome sight in the Sierra, which has seen a near-historic low snowpack this year.

The snow won’t be going anywhere for a while: Temperatures in South Lake Tahoe are expected to dip to 5 degrees Tuesday, 7 degrees Wednesday, 14 degrees Thursday and 15 degrees Friday.

The precipitation and the low temperatures stand in stark contrast to the unseasonably high temperatures and relentless sunshine that the region felt earlier this month. Many of Tahoe’s ski resorts were forced to close low-elevation runs while relying on their snowmaking machines to make up for the lack of snow.

But the snowy and icy conditions Monday caused major problems for travelers heading back from the mountains after the long holiday weekend. Chain controls were in effect for highways throughout the Tahoe area Monday, and motorists were advised to drive slowly, according to the California Highway Patrol.

Major traffic delays were reported on Interstate 80 and Highway 89 out of the Tahoe basin, according to the Placer County Sheriff ’s Office.

Back in the Bay Area, temperatures in San Francisco sank to the low 40s Monday morning and climbed up 10 degrees by midafternoon. Higher elevations — including Mount Diablo and Atlas Peak — fell well below freezing Monday morning, reaching 23 and 28 degrees, respectively, and reached mid-30s by the afternoon.

A shower passing over Berkeley left behind pellets of hail in the city that quickly melted once they hit the ground.

“We are starting to approach March and, by this point, our normal is closer to 60s,” said Matt Mehle, a meteorologist with the National Weather Service. “Just be mindful of pets you may keep outdoors. Now is the time to prepare for the cold weather.”