SAN FRANCISCO (KRON) -- Multiple rain systems are approaching the San Francisco Bay Area, with the first rainfall expected to begin Wednesday night. The first, weaker system will mostly impact the North Bay before the second, stronger system moves in on Friday, according to the National Weather Service. By 10 a.m. Thursday, Santa Rosa, Napa and San Francisco could see up to 1 inch of rainfall, according to forecasters.  The rain is expected to begin late Wednesday night, “well after sunset and the evening commute has ended,” KRON4 Meteorologist John Shrable said. As much as half an inch of rain could fall in areas of the East and South Bay, including Concord, Livermore and San Jose, NWS said. San Francisco Bay Area current weather conditions The second system is expected to bring more widespread rainfall, dropping higher totals across the region. Between Friday and Saturday, Santa Rosa is forecasted to receive up to 2 inches of rain, with Cloverdale possibly seeing up to 3 inches. Napa and San Francisco are estimated to get up to 1.5 inches, with the East Bay and South Bay getting up to 1 inch. (Graphic: National Weather Service Bay Area) The rain will coincide with king tides that will impact the Bay Area’s coastal areas between Friday and Sunday. Localized flooding is a concern due to the overlap, especially for areas with higher rain totals, according to weather officials. The Petaluma Fire Department warned that “the combination of these could cause minor river flooding, coastal flooding and hazardous beach conditions.” Bay Area king tides offer dramatic highs and adventurous lows Moving into next week, Shrable said models show a third wave of rain is likely to hit the Bay Area.