The Level 3 storm began shortly before 6 p.m. and is projected to continue until 9 a.m. The heaviest rainfall is expected between 1 a.m. to 7 a.m.
Santa Rosa is projected to get 2.28 inches of rainfall overnight - one of the highest projected totals across the Bay Area.
Resident Stephen Crane is concerned about flooding.
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"There's always a bit of prep getting ready for it because the streets can flood and out in west county. The rivers can flood," said Crane, as he powered on the leaf blower.
Residents across the area were seen securing holiday decor, clearing out the gutter, and stocking up on sandbags and sump pumps.
"Our advanced prep is staying home," said James Dougdale.
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Dougdale and his partner extended their holiday visit to avoid a mess on the roads overnight.
Last year's atmospheric river, a December 2021 storm, brought widespread flooding and power outages across the Bay Area. A similar scene is expected overnight, bringing a messy morning commute with wind gusts between 35 to 50 miles per hour Tuesday morning.
"If we don't have electricity today, then we'll use candles. We have plenty of them in the store," said Elise Pierce, a local store manager.