Sonoma County expected to get more rain through weekend and into next week

Even as the current storm continues to bring passing showers across the North Bay, a parade of three or more “waves of moisture” is expected to yield more rain beginning Sunday morning and through the early part of next week, according to the National Weather Service.

“We are expecting another storm system to arrive as early as Sunday morning from the north that will bring wet conditions through at least the first half of Sunday,” said Matt Mehle, a weather service meteorologist.

Mehle said Sunday afternoon will see a brief break in the rain before more storms arrive Sunday night and Monday morning. “Monday will be pretty wet for the entire day,” he said.

“We don’t finally dry out until later in the week — possibly Thursday we have kind of drier conditions developing,” Mehle said. “So we have at least three or four additional waves of moisture moving over the North Bay, bringing additional rain chances and also some higher elevation snow chances.”

But Mehle stressed that future snow is expected to fall at much higher elevations than what was seen in recent days.

“Places at 2,500 to 3,000 feet should see snow, but not down to 250 feet,” he said. “We had an observation from Cloverdale that had about two to three inches of snow and they were at 250 feet elevation. We also had another report near Cloverdale ... they were at 331 feet and they also had measurable snow.”

Snow in the North Bay is not uncommon in February, though it usually doesn’t fall any lower than 2,000 feet, Mehle said.

The most recent storm brought numerous calls of downed trees and power lines across the region. Cal Fire Capt. Leah Simmons-Davis said several roadways, including Highways 128 and 175 in Mendocino County, are experiencing storm-related closures.

“There are numerous trees and lines down across roads,” Simmons-Davis said. “Unless you absolutely have to go somewhere, it’s definitely a good idea to just hunker down.”

Mehle said temperatures are expected to be higher than in the past week, but still below normal. The high Saturday across the North Bay will “struggle to hit 50 degrees,” he said, adding that higher elevations, such as Mount Saint Helena will barely hit 40 degrees.

The storm system that brought snow down to 250 feet was caused by a rare confluence of conditions, Mehle said. Usually, when a storm arrives in the North Bay it is followed by cold air. This time, he said, the cold air preceded the storm.

He said storm air masses that come into the region are often modified by moving over the warmer Pacific Ocean. The recent storm took a slightly different track and brought much colder air and a “less modified air mass,” Mehle said.

“There were kind of two things at play there,” he said. “We had cold air in place ahead of the storm but also the air mass that wasn't as modified.”

He said the last low-elevation snow in the region occurred in 2019 and the last sea-level snow fall, which was not much more than a dusting, took place in 2011.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @pressreno.