"We don't get many Atmospheric River events in May," said Nicco.
On Saturday, the Bay Area will be hit with a 1 on the Storm Impact Scale, followed by more rain Sunday and Monday.
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Nicco's AccuWeather forecast shows light to moderate rain will move into the North Bay Saturday afternoon.
"Expect several hours of rain in the North Bay during the overnight hours. The rain will start to move south as we head into Sunday" said Nicco. "The rain will turn into showers Sunday night with a chance of thunderstorms into Monday."
Small hail is possible.
"We have a chance of lingering showers Tuesday before we see warmer and dryer weather on Wednesday," said Nicco.
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