It’s going to be rainy and cold across Sonoma and Napa counties. Here’s what to expect and when

It seems warm summer days are over for Sonoma and Napa counties as overnight lows are expected to drop to about 30 degrees.

Much of the North Bay should expect light showers, low overnight temperatures and potential elevated fire risk through the end of the week, according to Rick Canepa, a meteorologist with the National Weather Service’s Monterey office.

A cold front Wednesday led to some rain over the area and a new front moving in Thursday will compound its effects.

Temperatures will dip to the mid- to upper 30s in the interior valleys and the 40s in the hills and mountains through Saturday night. Another round of light rain ― about 1/100 to 2/100 of an inch ― can also be expected Thursday night into late Friday morning.

Over the weekend, however, offshore winds from the northeast will push out colder air and usher in a higher fire risk.

Highs on Saturday will likely peak in the mid- to high 60s in the interior valleys, though relative humidity will drop overnight Saturday and 15 to 20 mph winds are forecast.

The weather service hasn’t issued any fire risk advisories, Canepa said.

“Fuel moistures have elevated pretty well for this time of year since we have had some precipitation already,” he said. “It’s good to see that going into any potential offshore wind event.”

But “it’s something we will be monitoring closely,” Canepa said about potential fire risk.

You can reach Staff Writer Madison Smalstig at madison.smalstig@pressdemocrat.com. On Twitter @madi.smals.