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.
UPDATE 6:40 P.M. - Firefighters continue to make progress on the Washington Fire. As of late Thursday afternoon, containment stood at 15 percent. Crews remain focused on keeping the fire away from the community of Markleeville.
The Sacramento Metropolitan Air Quality Management District said the region's air quality is forecast to be unhealthy for sensitive groups Thursday.
Warmer weather is bringing out snakes, including rattlesnakes, in Northern California.
With high temperatures, people and their pets hit the water to cool down.
Some scattered showers are in the forecast for the Sacramento Valley and throughout Northern California Thursday. While not much precipitation is expected, a winter weather advisory has been issued for elevations above 6,500 feet south of Highway 50.