The atmospheric river that has inundated California is a mixed blessing, at once easing drought conditions and promoting threatened fish species while also nourishing the growth of vegetation that will eventually fuel future wildfires. After severe drought conditions for most of this century, California is forecast to have its second wet year in a row, though not quite as wet as the exceptional precipitation of a year ago. As of Monday morning, precipitation in Northern California so far this year was only 85% of its historic average, said Jay Lund, vice director for the Center for Watershed Sciences at the University of California, Davis.