The second storm, forecasters say, could bring thunder and dump up to 2 inches of rain in central and southern valleys, 2 to 4 inches in the foothills and up to 6 inches in some mountain spots.
State water officials plan Thursday to survey the anemic mountain snow pack, and will likely find that California's precipitation is badly lagging what's needed to quench the region's thirst. 2013 was California's driest year on record.
In Nevada, the first of back-to-back storms dropped several inches of snow at Lake Tahoe and up to a foot and one-half on the mountain ridges.
A winter weather advisory was put into effect from 4 p.m. Wednesday to 10 a.m. Thursday for the Reno-Tahoe area, south to Mammoth Lakes.
The second wave of wetter weather begins Friday night into Saturday.
As thousands of travelers hit the roads for the Thanksgiving holiday, a storm is dumping rain and snow in the Sierra Nevada and the Lake Tahoe region.
UPDATE: The National Weather Service has canceled a tornado warning for Sacramento County residents near Elk Grove and Wilton as of 6:30 p.m. Monday. Winds up to 25 miles an hour moved over Wilton.
UPDATE: The National Weather Service has issued a Flash Flood Watch through 9 p.m. Monday for the King Fire burn area in El Dorado and Placer counties.
The Pacific Storm system brought some slight improvement to drought conditions in California and Nevada last week.
The National Weather service has canceled a flash flood warning for Colusa, Lake and Yolo counties for Monday afternoon. A "flash flood watch" remains in effect until 8 p.m. for the burn areas.