Sonoma County temperature records fall as warm, dry winter days take hold

A wintertime mass of warm, dry air baking California shattered daytime temperature records around the Bay Area Saturday, including a record in Sonoma County that has stood for 112 years.

The toasty temperatures, which are expected to continue for at least another week, are occurring during what is typically the wettest time of the year, which is worrisome to those watching the region’s water supplies.

“It’s nice to enjoy the warm weather. Unfortunately we’re behind in rain this year and this is going to push us further behind where we want to be,” said Duane Dykema, a meteorologist with the National Weather Service in Monterey.

Nine different Bay Area locations broke records for Feb. 3, including two in Sonoma County.

The mercury peaked in Healdsburg at 80 degrees, toppling the previous high of 76 set in 1906.

“It’s a very significant record,” Dykema said, noting that the Healdsburg weather station is one of the oldest in the North Bay.

Santa Rosa’s high of 76 was also a new record, soaring past the previous high of 73 degrees set in 2009.

Other notable temperatures included 82 degrees in Cloverdale, which was the highest temperatures recorded for the day in the county, though not an official record, Dykema said.

That’s because the measurement is from a private weather station. The official Weather Service temperature data for Cloverdale lags the private readings, he said. But if the 82 is confirmed, it would be the highest for the city on Feb. 3 in 40 years, he said.

Other notable temperatures included The Sea Ranch at 70 and Petaluma at 76.

The warm days are caused by a ridge of high pressure parked off the West Coast. It is causing both subsidence, where the air stalls and warms as it sinks, and offshore winds, which cause air to heat as it moves over the land, Dykema explained.

Temperatures will ease back slightly over the next couple days, but barely enough to notice. The warm pattern appears likely to persist for a week to 10 days, he said.

That’s making a dry winter look more and more likely.

Local reservoirs remain in fair shape now because of last winter’s deluge, with Lake Sonoma at 84 percent of capacity, the lowest in two years and below the 10-year average, according to the Sonoma County Water Agency.

Since Oct. 1, just 13 inches of rain have fallen in Santa Rosa, or 61 percent of normal. And that’s just a trickle compared to the 40 inches that inundated the area by this time last winter.

Most rain typically falls in December, January and February, “so we’re starting to run out of time here,” Dykema said.

You can reach Staff Writer Kevin McCallum at 707-521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @srcitybeat.