The National Weather Service says a significant storm will bring between a quarter and a half-an-inch of rain to the valley and up to 2.5 inches of rain to the Sierra.
David Rowe with the weather service says there will be snow too.
"Probably about a foot to a foot and a half at the ski areas and maybe 2 to 3 inches down to about 4,500 feet," says Rowe.
Rowe says there are also flooding concerns in areas scarred by wildfire last summer -- for example the Rim Fire near Yosemite.
"When you get heavy rainfall intensity in a short amount of time, you tend to get mud and dust and debris left over from the fires last summer that'll accumulate and run downhill," he says.
Rowe says this will be a significant storm, but the region needs a series of these storms to start recovering from the drought. He says the forecast is dry again for the weekend and early next week.
Rowe urges valley commuters to use caution, especially Thursday morning, when the roads are likely to be slick, and says chains will likely be required in the Sierra.
The weather is about to change. Attached is the NOAA prediction for snow onI-80. Be prepared for winter driving. pic.twitter.com/kEvvfGXHAo— Caltrans District 3 (@D3PIO) January 28, 2014
A new report shows there are certain highways in California that are "hot spots" for wildlife-vehicle collisions.
A new report says more people in California are at risk from wildfire and fires are starting earlier and are three times larger than in the 1970s.
A new study finds California’s Central Valley has three times more water beneath it than previously estimated.
UPDATE June 26: Fire managers says the Erskine Fire near Lake Isabella in Kern County has grown to 43,460 acres and is 40 percent contained. Two people have died, and more than 250 structures have been destroyed and an additional 75 damaged.
Four consecutive years of drought, millions of dead trees and summer heat, are all factors as thousands of firefighters work to control wildfires in California.