It might feel like spring on Wednesday, with high temperatures in Los Angeles reaching the 70s, but Thursday will be a “shock to the system,” weather experts say.
Temperatures Thursday and Friday are expected to drop 15 to 20 degrees from Wednesday’s highs as a cold storm blows through California, bringing low-lying snow, showers and a risk of severe thunderstorms.
Parts of Southern California could experience historically low temperatures Friday, said National Weather Service meteorologist Mike Wofford.
“With the system coming in, we’re going to see a dramatic drop (in temperatures) tomorrow,” Wofford said Wednesday from the weather service’s Oxnard office. “(There will be) a temperature drop of almost 20 degrees, and even cooler on Friday.”
High temperatures in most inland areas are expected to peak Wednesday in the 70s, possibly reaching 80 degrees, Wofford said. But temperatures will quickly give way to highs in the 50s on Thursday and Friday.
“Friday’s high temperatures across the coasts and valleys will be in the mid to upper 50s, which would be cooler than normal in early January and still April!” forecasters said in the weather service’s daily update.
Along with the cold weather, snow levels will fall significantly lower than most storms, with accumulating snow possible on all major mountain passes in Southern California, including the Grapevine, the weather service warned.
“Typically, we don’t have a lot of storms where snow levels go down to 3,000 feet or potentially to the bottom of the Antelope Valley,” Wofford said. He said accumulating snow in the Antelope Valley was unlikely, but he expected the region to see a mix of rain, snow and sleet. Nearby foothills could get up to an inch of snow, he said.
Snow is expected across Southern California Thursday and Friday night, with 1 to 3 inches likely between 3,500 and 4,500 feet elevation and more than 3 inches above 5,000 feet.
The cold nature of the storm makes it less humid than other recent storms, but the cold air increases instability in the atmosphere, weather officials said. Showers Thursday and Friday could include thunderstorms, which could bring hail, downpours, small tornadoes and waterspouts — although that will be isolated, Wofford said.
Rain totals will mostly stay under a half inch, with some locally higher accumulations where thunderstorms occur.
Temperatures in central California are also expected to drop 20 degrees by Thursday, officials said, from highs in the 70s to around 50 or 60 degrees.
In the southern Sierra Nevada, a winter weather advisory will go into effect Wednesday evening and remain in effect through Friday, with 6 to 12 inches of snow expected above 3,000 feet.
“Travel will be very difficult,” the warning said. “High winds could damage trees. Cold wind chill temperatures as low as 20 degrees below zero could cause frostbite on exposed skin in as little as 30 minutes.
In the state’s northwest, weather officials warned of freezing and “abnormally cold” temperatures starting Wednesday evening, with snowfall up to 1,500 feet and mountain temperatures dropping between 15 and 25 degrees.
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