Sonoma County under heat warning for weekend; officials forgo opening cooling stations

Sonoma County residents will likely experience relentless heat this weekend, according to National Weather Service meteorologists.

The weather service issued an excessive heat warning for 11 a.m. Saturday to 11 p.m. Sunday for the inland Bay Area, including portions of Sonoma and Napa counties.

This warning signals the North Bay will not see much reprieve from 90- to 110-degree daytime highs as overnight lows are forecast to be in the 60s across the valleys and 70s in the hills, according to a weather service news release.

Northern portions of Sonoma and Napa counties have a higher chance of seeing highs above 100 degrees on Saturday and Sunday, whereas areas more south, such as Santa Rosa, are more likely to see the 90-degree temps.

Santa Rosa had a 23% chance of having high above 100 degrees. The city of Napa has a 3% chance.

Overnight lows in July typically dip into the 50s in the inland areas of Sonoma County.

The weather service initially published an excessive heat watch Monday, but upped it to a warning Wednesday as confidence for higher temperatures grew, weather service meteorologist Sarah McCorkle said.

The “extreme heat” is anticipated to increase the potential for heat-related illnesses, especially for residents spending more time outdoors. To mitigate heat exhaustion, individuals should hydrate, avoid strenuous activities during the day, look after those more susceptible to the heat ― such as older people and young children ― and seek spaces with air conditioning, like malls and libraries.

Meteorologists also are predicting a higher chance for vegetation fires, though no red flag warnings have yet been issued due to an anticipated lack in strong winds.

“There is definitely an elevated risk,” McCorkle said, referring to vegetation fire starts. “So, be careful.”

Sonoma County officials said they will not be opening cooling centers at this point because the conditions do yet warrant taking that action.

“The county Department of Emergency Management is monitoring the weather, but at this time we are not meeting the threshold to open cooling centers,” Matt BRown, a county spokesperson, said in an email.

According to criteria the county approved in early June, “we need to be at a National Weather Service Heat Risk Level 3 or greater for at least three consecutive days AND be under an excessive heat warning,” Brown said.

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