California's mountains could see rare August snow in weekend of 'weather whiplash'

An unusually strong, early-season cold front was moving across Northern California on Friday, bringing with it the possibility for rare August snow along the peaks of the Sierra Nevada.

A low-pressure system coming off the Pacific has created a few days of " weather whiplash ," which forecasters say will drastically drop temperatures and create favorable conditions for showers and thunderstorms Friday and Saturday — before rebounding to more typical August weather patterns by Sunday.

For the first time in over two decades, August snow could fall on some of the highest peaks of California's Sierra Nevada, most notably along the Tioga Pass and the tallest points of Yosemite National Park.

"Snow has not occurred [in August] here since 2003," the National Weather Service in Hanford wrote in its Friday forecast. "While this snow will not stay around very long, roads near Tioga Pass could be slick and any campers and hikers should prepare for winter conditions."

There's about a 50% chance for a dusting in the area early Saturday, forecasters said, and a possibility for brief snowfall across peaks over 8,000 feet in elevation.

“Getting something in late August is pretty early," said Tony Fuentes, a National Weather Service meteorologist in Reno, though he said it's not unheard of.

If anything does fall, "it's not looking like a lot of accumulation," he said.

Still, some Tahoe-area ski resorts will be on the lookout for snow Saturday morning, including Palisades Tahoe.

"It's exceptionally rare for our area to experience new snowfall in August, as it's typically one of the warmest months here in Tahoe," Patrick Lacey, a spokesperson for the resort, said in a statement. The resort said it hasn't seen August snow since 2004.

The shift in weather bringing the chance of snow will mostly give people an early "hint of fall ," including a chance for some record cold temperatures in the area, Fuentes said.

“Last time we had a cold front that dropped us to these temperatures in August was 2014," he said.

The Tahoe area will see some of the most dramatic drops, with highs Friday and Saturday about 15 to 20 degrees below seasonal averages. Tahoe City is forecast to tie the record for its coldest high temperature for the date — 58 degrees — while South Lake Tahoe's forecast high of 62 degrees is 5 degrees below the previous record.

The abnormally low temperatures will be felt across Northern California, but the chance for rainfall and thunderstorms is drawing the most concern.

Around the massive Park fire burn scar — which extends across much of Butte, Tehama, Plumas and Shasta counties — officials have issued a flash flood watch Friday and Saturday. The fire has burned nearly 430,000 acres and was 65% contained as of Friday.

"Moderate to heavy rainfall could trigger flash flooding of low-lying areas and debris flows around the Park fire burn scar," the alert said, adding residents should prepare for potential flooding.

Up to half an inch of rain is possible over a few hours from Friday night into Saturday morning, particularly over Shasta County and in the Redding area, according to the National Weather Service.

If thunderstorms develop, officials said the systems could create small hail, lightning and gusty winds, primarily in the northern Sacramento Valley.

The storm system will bring some gusty winds across the state, which could increase the chance of wildfires. Kern County, in particular, is expected to have an elevated fire risk through Saturday.

The switch away from these below-average temperatures will be just as quick, with seasonal highs expected to return by Sunday and Monday. Long-range forecasts even show that higher-than average temperatures are expected to return for the rest of the month.

This story originally appeared in Los Angeles Times .