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.
The National Weather Service is offering a more positive forecast for the likelihood of a wet December in California.
Snow and light showers are expected to return to the region.
It's was a wet commute for Sacramento-area motorists Thursday morning. But forecasters say it's expected to be dry this weekend.
The hot weather will be in the Sacramento region for a few more days, but some relief is on the way.
UPDATED: For the past two days in a row, Reno has logged record high temperatures.