LOS ANGELES (AP) — The first of back-to-back atmospheric rivers is drenching California. Heavy rain and gusty winds began hitting the state’s north on Wednesday before moving south along the coast and snarling the Thursday morning commute in Los Angeles. It has flooded roads, toppled trees and caused traffic accidents, but also dumped welcome snow in the mountains. Forecasters say the storm will be followed by a more powerful one on Sunday. The California Governor’s Office of Emergency Services has activated its operations center and positioned personnel and equipment in areas most at risk from the weather.