The rain that started Friday afternoon is expected to continue through today.
"The current system will keep raining through the day, tapering off by afternoon," said National Weather Service forecaster Steve Goldstein.
The sun may peek through the clouds on Sunday, but a new system is expected to roll that evening.
Goldstein said rain in the valleys averaged between a fifth and two-fifths of an inch.
Accuweather reported Carson City received .15 inches of moisture by 5 p.m. on Friday.
Snow levels rose and fell through the day on Friday, according to Goldstein, with snow levels dropping to Lake Tahoe's shores for a time before climbing back up.
The warm storm probably won't leave snow in the valleys, with snow levels near 7,000 feet through today and high temperatures in the mid-40s to lower 50s.
Overnight temperatures will drop to the 20s and Sunday is expected to be partly cloudy with highs reaching up to 50 degrees.
Squaw Summit reported 4-5 inches of new snow on Friday.
The storm expected Sunday may last through New Year's Eve, dampening outdoor events from Stateline to San Francisco.
An estimated 60,000 revelers are expected in Stateline this year.
Rain may also slow down San Francisco's popular New Year's Eve waterfront fireworks show.
P.J. Johnston, a spokesman for the city, said most folks likely already have made plans for the evening and said he doesn't think the rain will deter those celebrating at various indoor parties.
"I think that bad weather might affect the outdoor celebration along the Embarcadero, although we're still going forward with it and we still think there will be a pretty good turnout for the fireworks," Johnston said.
"Whether it's raining or it's shining, everyone celebrates New Year's in one manner or another. We've had rain and fog in the past, so I don't see why this would be any different," he said.
The storm is expected to dump as much as 2 feet of snow in the northern Sierra through today.