OAKLAND, Calif. - Two low-pressure storm systems are headed toward the Bay Area, expected to bring several inches of rainfall through the weekend. The first storm system is a warm, tropical moisture-heavy system arriving Thursday, followed by a more powerful, colder storm from the Gulf of Alaska on Saturday. Total rainfall through Sunday is expected to range from a half-inch to an inch-and-a-half for most areas, with up to 3-inches in the coastal ranges.