Rain in May? Not Unheard Of in Northern California But an Unusual Amount for Entire Month

Rain returns to the Bay Area this week, in surprising amounts for the month of May.

On Wednesday night and early Thursday, meteorologists expect the first system to soak the entire Bay Area and much of Northern California with about an inch of rain in most places. A second storm is forecast to arrive Sunday.

“We’re going to see a pair of fronts coming through the area,” said Jan Null, an adjunct professor of meteorology at San Jose State University.  “There’s a broad trough of low pressure off the coast.”

Rain in Northern California is hardly unheard of this late in the season. But by Thursday, most areas in the region could receive more rainfall from the storm than is typical for all of May, Null said.

The National Weather Service said that while it expects Wednesday’s storm to be “rather strong for this time of year, widespread damaging winds and flooding do not appear likely at this time.”The North Bay will likely see the heaviest rain, with about 1.5 inches of precipitation expected on Wednesday and Thursday, followed by another inch on Sunday, according to Null.  San Francisco could receive three-quarters of an inch of rainfall midweek and a half inch on Sunday. Rain in the South Bay and San Jose is expected to be less intense: a half inch from the midweek storm and a quarter inch on Sunday. “Bigger amounts farther north, but the whole area — we’ll be seeing rain on those days,” added Null.

Showers could continue into next week.  

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