Cooler

Oct 29, 2023

Northern California's interior is under a red flag warning for critical fire weather conditions over the coming days.

While thousands of Northern Californians were coping Wednesday with red flag warnings, critical fire weather, and forced power outages imposed by Pacific Gas and Electric Co., people in Calaveras and Tuolumne counties were looking forward to pleasant, cooler than normal daytime highs extending through the last holiday weekend of summer.

Late August and early September in recent years have roasted the Mother Lode. Sonora residents remember Sept. 1 last year brought the terrifying nighttime Woods Fire, when it was 104 degrees Fahrenheit that day and 106 the next.

If forecasts are correct, the county is luckier this year. Temperatures over Labor Day weekend are expected to be around 20 degrees cooler than normal in the Mother Lode, with Sonora daytime highs in the mid-70s Friday to Sunday, and highs in the mid-80s through next week.

The cool blast, coming from the Big Basin and the Eastside Sierra, could also bring dustings of snow above Ebbetts, Sonora, and Tioga passes by Sunday evening.

On Wednesday, red flag warnings for a dozen Northern California counties, from Amador to Shasta, were for north winds gusting to 35 miles per hour and low humidities that could cause fires to rapidly grow in size and intensity, the National Weather Service in Sacramento said in an urgent weather message. The warning was expected to expire at 8 p.m. Wednesday.

Before noon Wednesday, there were already at least five fires burning northwest of Redding.

The most extreme fire threats expected Wednesday were in the west Sacramento Valley along Interstate 5 and west of the 5.

Also before noon Wednesday, more than 8,000 PG&E customers in multiple counties were without power due to forced outages, which PG&E calls public safety power shutoffs.

“Between 2 and 4 a.m. this morning, we de-energized power to about 8,400 customers, primarily in the North Valley and Sierra region,” Joe Wilson, a PG&E vice president, said in a video posted online by the utility giant. “Mostly Shasta and Tehama counties, but we do have some customers that are affected in Glenn, Colusa, Yolo, and Butte counties as well.”

Information about resources available to customers coping with imposed outages could be found at www.pge.com/pspsupdates, Wilson said.

“Please be safe,” Wilson said. “This public safety power shutoff is something that we only do as a last resort to make sure we keep our communities, our customers, and our families safe.”

At midday Wednesday, winds were blowing southwest in the Sonora area with maximum gusts around 10 mph.

Sonora daytime highs in the low 90s were expected Wednesday and Thursday before the cooldown arrives, with the coolest temperatures — a high of 73 — expected Saturday. Overnight lows in the 50s are expected four nights in a row, Thursday night through Sunday night.

Over on the Eastside Sierra, forecasters in Reno said the coming cool spell was due to an “anomalously cold early season storm” dropping into Nevada and the rest of the Big Basin just in time for the holiday weekend.

Rain showers may develop in northern Nevada and portions of northeast California, approaching the Tahoe Basin on Friday, then spreading south on the Eastside through the weekend. This could bring weekend thunderstorms at high elevations on the Central Sierra crest, and the cold air mass could result in snow at elevations as low as 9,500 feet.

At Ebbetts Pass, there were 40% chances of showers with snow levels above 10,000 feet Saturday, Saturday night, and Sunday.

For Sonora Pass, there were 40% chances of rain and snow Friday night and Saturday, with overnight lows in the mid-30s and little or no snow accumulation expected. Chances of snow showers were expected again Saturday night and Sunday.

Overnight lows below freezing are expected Friday and Saturday at Tioga Pass, with chances of rain and snow levels above 10,000 feet on Sunday.

As of Wednesday, a five-station index for the Mother Lode’s watersheds showed Central Sierra precipitation at 63.9 inches since the current water year began last Oct. 1, 161% of average for the date Aug. 30.

Contact Guy McCarthy at [email protected] or (209) 770-0405. Follow him on X, formerly Twitter, at @GuyMcCarthy.