Northern California will transition into a wet pattern starting later today, that will continue through Christmas Day.
Current models suggest that the heaviest precipitation will occur Friday afternoon through Saturday afternoon. After a brief break, the wet weather pattern will resume again on Sunday afternoon with the heaviest precipitation anticipated from Monday afternoon through Tuesday afternoon.
Holiday travel will be impacted with slick roads. Travel delays and chain controls are likely across the Sierra Nevada.
The National Weather Service has issued a Winter Storm Watch for the Sierra Nevada above 4500 feet, from Friday afternoon through Saturday afternoon.
Total snow accumulations of half-a-foot to one foot is expected.
Total rain accumulation will range from one to four inches in the Mother Lode. Total rainfall in the Central Valley will range from 0.30 to 2.5 inches.
Localized urban and small stream flooding is possible.
Winds will be breezy to gusty at times
A Winter Storm Watch means there is a potential for significant snow accumulations that may impact travel.