The National Weather Service says a funnel cloud touched down near Roseville shortly after 6:15 p.m. Wednesday.
Fire Department Division Chief Kathy Finney tells the Merced Sun-Star (http://bit.ly/1dQfV8X) that 12 houses suffered roof damage and six reported fence damage. No injuries are reported.
The weather service says a tornado also touched down in Ordbend, in Glenn County. KNTV says there are reports of at least four twisters, which are rare for California.
The northern half of the state is experiencing wild weather including thunderstorms packing heavy winds.
An inch of rain was reported in some areas.
Showers are likely to continue through the weekend.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
Northern and Central California were drenched and wind-whipped Wednesday by wild weather that saw thunderstorms and reports of possible tornadoes but no major damage or injuries, authorities said.
"It's been pretty crazy today," said Holly Osborne, a meteorologist with the National Weather Service in Sacramento.
There were "showers this morning, then the clouds broke, and then showers and thunderstorms this afternoon and funnel clouds."
Heavy rain hit morning commuters in San Francisco but by the end of the day only about a half-inch of the much-needed rain had fallen.
Other northern and central areas generally saw a quarter- to a half-inch, with Stockton receiving about three-fourths of an inch and an inch recorded in a few places.
"Finally we're getting some rain," San Francisco resident Mike Vladimer told KGO-TV (http://bit.ly/P3IXM9). "We need it. It's been really dry."
San Francisco has received less than half of its average rainfall since last summer.
"So, I know people hate the rain here and I'm very not used to it," Vladimer said. "But at the same time, I've seen how low the water levels are. So hopefully this is getting over the mountains and into the reservoirs."
Tornado warnings were issued from around 3:30 p.m. to about 7:30 p.m. for some areas of Glenn and Placer counties above Sacramento, including the towns of Artois, Roseville and Rocklin.
Several funnel clouds were reported, Osborne said.
The north was in the midst of what forecasters were predicting would be the longest stretch of wet weather yet this year.
Showers were likely to continue through the weekend, especially from Friday afternoon through Sunday morning when the Sacramento Valley could get another half-inch to more than an inch of rain. The southern Bay Area could see up to a half-inch of rain, and the northern Bay Area could get as much as 1 to 2 inches, Osborne said.
The Sierras could receive 1 to 2 feet of snow above 7,000 feet.
But the showers might not end with the weekend, Osborne said.
"We're expecting unsettled weather even into early next week, so be prepared to bring your umbrella and rain boots," she said.