For the most part, temperatures in Sonoma and Napa counties aren’t expected to reach as high as they did on Tuesday, but weather officials are still recommending extreme caution.|
MARTIN ESPINOZA
THE PRESS DEMOCRAT
This week’s heat wave across the North Bay and along the North Coast is expected to crest Saturday, with widespread temperatures back in the triple digits, a few degrees hotter than Friday.
For the most part, temperatures in Sonoma and Napa counties aren’t expected to reach as high as they did on Tuesday, but weather officials are still recommending extreme caution, citing health risks and wildfire danger.
The current red flag warning, extended on Wednesday into the weekend, expires at 9 p.m. Saturday. The warning is for North Bay interior mountains, East Bay Hills and Santa Cruz Mountains.
Lamont Bain, a meteorologist with the National Weather Service, said the red flag warning covers “higher terrain” of Sonoma and Napa counties, as well as much of Lake and Mendocino counties, where temperatures are higher, humidity is low and critically dry fuel abounds.
Meanwhile, local public health officials on Friday extended a separate heat advisory into next week, in response to the National Weather Service extending its own excessive heat warning until 11 p.m. Wednesday, July 10.
On Friday, high temperatures in Sonoma County ranged between mid to upper 50s along the coast to 104 degrees inland in Cloverdale. Santa Rosa logged 95 degrees at the Charles M. Schulz-Sonoma County Airport.
It was in the mid 70s in Bodega Bay, and about 56 just south of there.
Temperatures in Napa County on Friday ranged from 90 degrees in American Canyon to about 95 in Napa. In the Lake Berryessa region, one of the hottest, it got the mercury edged several degrees above 100.
On Saturday, highs are expected to be one or two degrees hotter across the region. Bain said northern Sonoma County, near Cloverdale, could get temperatures as high as 110 degrees.
Some places on the North Coast could see temperatures peak above Tuesday’s highs.
In Ukiah, where the mercury reached 108 degrees on Tuesday, is expected to hit 115 on Saturday, weather officials said.
As temperatures began climbing Friday, local health officials warned of the dangers of heat exposure.
In a press release announcing the extension of the local heat advisory, Dr. Tanya Phares, Sonoma County’s health officer, said current weather conditions can cause heat stroke, worsen chronic health conditions and lead to severe complications and even death.
“Extreme heat is very taxing on the body and significantly increases the potential for heat-related illnesses, especially for those working outdoors or participating in outdoor activities,” Phares said in the statement.
Symptoms of heat stroke include: body temperature of 103 degrees or higher; hot, red, dry or damp skin; fast, strong pulse; headaches; dizziness; nausea; confusion; and passing out.
The local heat advisory applies to inland areas of Sonoma County where high temperatures are forecast to range from the mid-high 90s to the low 100s. Santa Rosa is expected to remain in the 90s all next week, county officials said.
The current heatwave has heightened concerns about wildfire in the area, especially with the introduction of fireworks over the Fourth of July weekend. Use of any fireworks, even state-approved ones, is illegal across Sonoma and Napa counties outside of the July 4 holiday.
On Thursday into Friday, Cal Fire and local fire crews received hundreds of calls for service and responded to dozens, including several small fires linked to fireworks, as well as medical calls.
Karen Hanco*ck, a spokeswoman with the Sonoma County Fire District, said higher humidity overnight on Thursday and low wind aided firefighting efforts but the heat will remain a concern over the next few days.
The holiday weekend “always puts us on edge,” Hanco*ck said, but even more so this year with early fire activity and warm weather.
“We just want everyone to stay safe,” she said.
Bain, the National Weather Service meteorologist, said the current heat wave is caused by a high pressure system that’s situated itself over Northern California. The National Weather Service said much of the Western United States is experiencing a similar heat wave.
Such high pressure systems generally tend to suppress the marine layer, which offered some relief on Thursday but less so this weekend.
The good news is that there’s been an absence of widespread offshore winds, which would increase fire danger. Even so, Bain said though there isn’t a strong wind component to the current heat wave and red flag warning, local residents should be aware of the danger of wildfire.
“The fields are just so dry, it doesn't take a lot to get an ignition,” he said. “Obviously, with the Fourth of July and even holiday weekend, people like to shoot off fireworks and that can second certainly cause (fire).”
You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @pressreno.