Forecasters say a "potent" late-season storm system is heading toward Northern California.
The National Weather Service says showers arriving Thursday will turn into widespread rainfall, high winds and mountain snow.
Storm warnings posted from the Oregon border down through the northern Sierra Nevada call for about 6 inches (15 centimeters) to 12 inches (30 centimeters) of snow at elevations above 4,500 feet (1,372 meters) and between 2 feet (0.6 meter) and 4 feet (1.2 meters) at elevations above 6,000 feet (1,829 meters).
Gale warnings and small craft advisories will go into effect for the coastal waters Thursday afternoon.
The Reno weather service office says this is all the result of another so-called atmospheric river, a plume of moisture stretching out into the Pacific.