Flood Watch For Petaluma, North Bay Issued By NWS

PETALUMA, CA — A National Weather Service flood watch for Petaluma and several other cities across the North Bay is slated to go into effect Thursday night as an atmospheric river brings heavy rains to the region. A flood watch means that based on current forecasts, there is potential for flooding — in this case small creeks and streams as well as poorly drained areas Friday into Saturday, especially in the North Bay and Santa Cruz Mountains — and that residents within the watch area should remain alert should a flood warning be issued.

"From late tonight through Saturday morning, periods of rain, heavy at times, are forecast to fall over the North Bay region and Santa Cruz Mountains including the coastal ranges of San Mateo and Santa Cruz counties," weather service officials say in the flood watch.

The flood watch includes the cities and communities of: Tamalpais-Homestead, Sausalito, Santa Rosa, South Santa Rosa, Napa, San Rafael, Petaluma, Novato, Rohnert Park, Angwin, Lagunitas-Forest Knolls, Woodacre, Scotts Valley, Boulder Creek and Day Valley.

Rainfall totals are forecast to range from 2.5 to 3.5 inches in the North Bay valleys and from 4 to 6 inches in the North Bay and Santa Cruz Mountains with locally higher amounts in excess of 8 inches possible.

Forecasters with NWS San Francisco Bay Area say mud and rock slides are also possible with this atmospheric river.

"During periods of heavy rain ponding of water on roadways is likely," forecasters said. "Extreme rainfall rates over recent burn scars could potentially trigger flash flooding or mudslide/debris flows across and downstream from the burn scars."

Based on rainfall projections Thursday morning, NWS forecasters say North Bay's mainstem rivers such as the Russian River and Napa River ma see "significant rises late this week and into the weekend, but remain well within their banks."

"However, smaller rivers and streams could flood, especially if heavy rain rates persist across a watershed longer than anticipated," weather service officials said.

Those living in areas prone to flooding "should be prepared to take action should flooding develop."

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