The Bay Area is in the midst of one of its wettest Januarys in the past 15 years, including record rainfall in Santa Rosa, and more is on the way. After the first in a series of storms soaked the Bay Area on Wednesday into Thursday morning, drenching Santa Rosa with more than 3 inches of rain, two more systems are taking aim at the region. The next soaking was expected to begin late Thursday night and deliver rainfall totals ranging from a half-inch to 1 inch to most Bay Area cities, said Bob Benjamin, a forecaster with the National Weather Service.