How Tropical Storm Hilary will impact Sonoma County

North Bay residents on Monday will experience remnants of onetime Hurricane Hilary in the form of high humidity, potential isolated rain and thunderstorms, National Weather Service meteorologists said.

The storm, now weakened to a post-tropical cyclone as it makes it way through Nevada, made landfall in Southern California on Sunday and caused power outages, downed trees, school closures and mudslides.

The impact to the Bay Area is expected to be more subtle, with the exception of potential thunderstorms, said Matt Mehle, a meteorologist with the weather service’s Monterey office.

“The Bay Area definitely did not to see the major impacts of Hilary,” Mehle said. “The biggest concern that we have when it comes to Hilary impacts, especially later today, is if we do get thunderstorms to develop.”

“Those have a chance of producing gusty winds, brief heavy rain and lightning and thunder with it,” he added.

The chance for scattered rain and storms in the North Bay is about 15%, bringing anywhere from a few hundredths to 1/4 of an inch, though the latter is far-fetched, meteorologist Dalton Behringer said.

The weather service is also monitoring wind gusts, which could approach 25 to 30 mph in certain portions of Sonoma and Napa counties.

Most likely the biggest change for residents will be humidity slightly higher than usual ― triggered by the tropical air mass accompanying Hillary ― which will make the lower-than-normal temperatures hovering in the 70s to seem a little bit warmer, Mehle said.

“Residents in the Bay Area will also no notice that it feels a little on the muggy side,” he said. “It's gonna feel a little bit more unusual.”

The humidity and storm chances will fade Monday night into Tuesday, when high pressure will build and flip the forecast to a warming trend through Thursday.

Temperatures across the interior portions of the North Bay will be back in the 90s by Wednesday, meteorologists said.

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