ST. HELENA (CBS SF) — Parts of the North and East Bay got a May surprise Thursday when a storm cell brought some areas brief downpours of significant rain and even hail.

The unusual weather comes the same day that some of those same areas were designated as regions under exceptional drought.

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Dark clouds swept down from the North Bay starting Thursday afternoon, bringing showers to parts of Napa County before moving south to Danville, Walnut Creek, Concord and Martinez.

And, as one might expect with unseasonable showers, there was a rainbow spotted in the East Bay.

While one of those areas of showers was dissipating as it moved over San Ramon by early evening, at the same time, a second cell delivered more showers in Wine County at around 6 p.m.

At one point, the cell over St. Helena even produced a lightning strike early Thursday evening in addition to earlier hail.

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While the storm cells were expected to largely fall apart over the next couple of hours as the sun goes down, there is a possibility a few more showers pop up over the North Bay Friday.

Meanwhile, the unusual weather was not just happening in the immediate Bay Area.

Tonya Daugherty was visiting Truckee from North Carolina on Thursday. She wasn’t expecting snow during her trip to the Sierra.

“Nobody back home is going to believe this,” she said.

A late spring Sierra storm even caught locals off guard. Truckee residents heard about the winter storm advisory but didn’t expect to see snow flurries or a winter wonderland this late in May.

“I’m used to the snow, but I’m not used to the snow when it should be almost summer,” said Mike Lake.

“Usually the weather is really nice during this time of year but I guess it just decided to up and dump on us randomly,” Talia Moore said.

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But not everyone was surprised. Scott Lee says he’s seen snowfall in the Sierra well into summer.