"We have a lot of ground to catch up on," said Brad Sherwood, spokesman for the Sonoma County Water Agency.
The city needs about 13 inches of rain to match 1977, the second year of one of the worst droughts in California history, he said.
Santa Rosa gets an average of 0.19 inches of rain a day in January and 0.21 inches a day in February, the third and second wettest months of the year, respectively.
December, the wettest month, totalled just 0.41 inches last year.
Virtually all of the state is in similar jeopardy, according to the U.S. Drought Monitor's report Thursday, showing that 98.6 percent of the state has an extreme to exceptional drought.
Extreme drought covers the San Francisco Bay area and extends along the coast from Humboldt County to Orange County.
For the first time in at least 14 years, the Drought Monitor map puts part of California in the exceptional drought category, a condition currently found in only four other parts of the continental United States.
A roughly 220-mile stretch of the San Joaquin Valley from Monterey to Bakersfield, covering nearly 9 percent of the state, is exceptionally dry, the map says.
Impacts of the condition include fallowing of farmland, wells running dry and little or no rangeland grasses for cattle to graze, prompting livestock sell-offs, the report says.
North Coast grape growers are bracing for substantial crop loss this year due to the drought, and state officials say the drought will likely cost farmers hundreds of millions of dollars.
Central Valley farmers lost $340 million in revenue in the 2009 drought, said Josh Eddy of the California Department of Food and Agriculture.
About 285,000 acres were fallowed and 9,800 jobs were lost, according to a University of California report.
"We know that this drought is trending to be much more severe and more widespread," Eddy said, referring to the drought as "a slow-moving crisis" with a toll that remains to be seen.
Santa Rosa's seasonal rain total through today is 2.09 inches, compared with 23.39 at the same time last year.
The city typically gets 32.2 inches in a rain season from July 1 to June 30.
A Sunday night storm is likely to pass south of the area, Strait said.
A system due around Feb. 8 "might be a decent storm" with as much as an inch of rain, he said, adding that forecast is "very cautionary."
A weakening in the offshore high pressure ridge allowed Wednesday's rain to slip into the area and it may now be "somewhat less capable" of blocking storms out of California, said Daniel Swain, a Stanford University graduate student who posts the California Weather Blog.
"But there is still no sign of the kind of sustained, heavy precipitation we would need to reduce drought severity," Swain said in an e-mail.
The U.S. Seasonal Drought Outlook says that drought will persist or intensify through April 30 all along the West Coast, as well as Nevada and much of Idaho, Utah and Arizona.
The report by the National Weather Service's Climate Prediction Center bases its forecast for California on a light Sierra snowpack and anticipated below-average rainfall.
The Sierra got its first significant winter storm in nearly two months on Thursday with up to 2 feet of snow expected at upper elevations in the Tahoe area, the Associated Press reported.