The National Weather Service says this week's storm could bring 1 to 2 inches of rain to the valley -- up to 5 inches could fall in the foothills.
Meteorologist Jason Clapp says the heaviest showers are expected later.
"The thing to be concerned about this afternoon is as the low moves in closer is the potential for getting some isolated thunderstorm activity, mainly late afternoon and the evening," says Clapp.
Clapp says rain in Sacramento was about 50 percent of average for November-- even after last week's storm.
Meanwhile, the National Weather Service is keeping an eye on potential debris flows in areas affected by the King Fire and the Rim Fire.
7 A.M. Snow, rain and gusty winds are all on tap for California as a powerful Pacific storm moves across the state Tuesday.
Forecasters say the rainfall is expected to be widespread and heavy at times, raising the possibility of mud and debris flows from slopes scarred by wildfires.
Heavy snow is forecast for the Sierra Nevada.
The rain also slowed the morning commute Tuesday. There were reports of accidents and some flooding on roadways.