‘Inside slider’ to bring dire wildfire weather to parts of California
By NSA staff| Posted: October 18, 2024
By Amy Graff,
Senior News Editor
Oct 15, 2024
Oct. 15, 6:42 p.m. Pacific Gas and Electric warned Tuesday it could cut power in five Bay Area counties beginning on Thursday due to dry and windy weather conditions that could heighten the wildfire risk across that state, according to the utility’s website.
In all, 30 California counties could face Public Safety Power Shutoffs from Thursday through Sunday, including Alameda, Contra Costa, Napa, Solano and Sonoma counties in the Bay Area.
Oct. 15, 3:05 p.m. Confidence is increasing that breezy offshore winds will heighten wildfire risk across California coming days, and the National Weather Service upgraded several fire weather watches for Thursday through Saturday to more severe red flag warnings.
Get the latest information on warnings from the weather service’s website.
Oct. 15, 11:25 a.m. A chance of light rain is coming to California, but meteorologists with the National Weather Service say the bigger story in the Golden State is an offshore wind event forecast to increase wildfire risk Thursday through the weekend. These desiccating winds that blow from inland areas toward the coast dry out vegetation and fan wildfire flames.
“This is going to be something that a good portion of the state is going to be impacted by,” said Alexis Clouser, a meteorologist with the weather service’s Monterey office. “Things are going to be ripe to start a fire if there’s a source of a spark.”
San Francisco Bay Area will experience “the biggest offshore wind event we’ve seen so far,” she said. As of Tuesday, it appeared winds will not be as strong in Southern California as in the northern part of the state, but the forecast is still evolving.
Offshore winds of 20-30
Skies were mostly clear over California on Tuesday, with the exception of some fog at the coast. The sunshine won’t last for long, as a weak storm system from the Gulf of Alaska is expected to impact the state Wednesday and Thursday, bringing widespread cooling and a chance for light rain and drizzle. The best chance for rain will be in far Northern California, including the northern Sierra, where rainfall totals could range from 0.1 to 0.25 inch, said Ashton Robinson Cook, a meteorologist with the weather service’s Weather Prediction Center.
The Sacramento Valley could see up to a tenth of an inch of rain, and on Wednesday afternoon and evening there’s a slight chance for thunderstorms in the areas of Mount Shasta and Lassen Volcanic National Park, the weather service said. In the greater Bay Area, earlier forecasts suggested the region could see a tenth of an inch or more, but Clouser said on Tuesday that the storm is trending drier. Most locations, from Sonoma to Monterey counties, will see no rain to a couple hundredths of an inch.
“This storm is not carrying too much moisture with it, so it’s not bringing much rainfall,” she said.
Coastal locations of Southern California could see some drizzle on Wednesday and Thursday, said Rose Schoenfeld, a forecaster with the weather service’s Los Angeles office. “Our best chance for rain for Southern California is Thursday overnight into early Friday morning,” she said. “There’s maybe a 10% to 20% chance in Los Angeles County.”
Thursday into Saturday, a second storm system known as an “inside slider” is expected to impact California. Unlike weather systems that come off the Pacific Ocean, this system is expected to track across inland areas, dropping down into Northern California from the Pacific Northwest and swinging across Southern California before heading into the desert Southwest, Clouser said.
“The way it sets up, you get the winds flowing in a way that they become offshore,” she said.
Weather service offices in Northern California have already issued fire weather watches from 11 a.m. Thursday through 8 p.m. Saturday for a large portion of the region, including the Sacramento Valley and the foothills, southern Lake County, the interior Bay Area, the city of San Francisco, the San Francisco Peninsula coast and the San Francisco Bay shoreline.
“Any fires that develop will likely spread rapidly,” the weather service warned.
Similar watches are likely to also be issued in parts of Southern California. On Thursday night, “the winds will be at their strongest” between San Luis Obispo and Los Angeles counties, said Schoenfeld.
“The story for winds is Thursday into Friday, and then a lingering offshore Santa Ana pattern into Saturday morning,” she said. She added that this will be a weak to moderate wind event for Southern California.
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2024
