The service says there is a 33 to 39 percent chance of the Sierra receiving more than five inches of precipitation, which is the average for the month.
Meteorologist Michelle Mead says there's a lack of high pressure in the atmosphere off the coast of California.
"The ridge has relaxed to the point that we're starting to see the polar jet stream bring some of those systems into the Pacific Northwest and into northern California." Mead says this is a typical pattern for this time of year and is not necessarily an El Nino pattern."
She also says it's unlike last year when a ridge of high pressure off the coast of California blocked storms that carried water.
"All the storm systems would get shoved north into Canada and the Pacific Northwest last year at this time. But, the long-range models say it doesn't look like that's going to redevelop at least through the end of November and into December."
The National Weather Service expects as much as four inches of water from rain and snowstorms in the Sierra from now thru Saturday.
California's precipitation total for this time of year is about half of normal.