It might feel like spring Wednesday, with highs across Los Angeles reaching into the high 70s, but Thursday is going to be a “shock to the system,” weather experts say.
Temperatures on Thursday and Friday are expected to drop 15 to 20 degrees from Wednesday’s highs as a cold storm blows across California, bringing low-elevation snow, showers and the potential for severe thunderstorms.
Some Southern California areas could feel historic low temperatures Friday, National Weather Service Meteorologist Mike Wofford said.
“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] an almost 20-degree drop in temperatures, and even cooler on Friday.”
Highs across most inland areas Wednesday are expected to peak in the high 70s, possibly reaching 80 degrees, Wofford said. But the temperatures will quickly give way to highs in the 50s on Thursday and Friday.
“Friday’s max [temperatures] across the coasts and [valleys] will be in the mid- to upper 50s, which would be cooler than normal in early January none the less April!” forecasters said in the weather service’s daily update.
Along with cold weather, snow levels will drop significantly lower than most storms, with accumulating snow possible on all of the major mountain passes in Southern California, including the Grapevine, the weather service warned.
“In general, we don’t get that many storms where snow levels drop to 3,000 feet or potentially down the Antelope Valley floor,” Wofford said. He said snow accumulation in the Antelope Valley isn’t likely, but he expected the area will get a mix of rain, snow and sleet. The nearby foothills could get up to an inch of snow, he said.
Snow is expected in Southern California on Thursday and Friday night, with 1 to 3 inches likely between 3,500 and 4,500 feet in elevation and more than 3 inches above 5,000 feet.
The storm’s cold nature is making it not as moisture-heavy as other recent storms, but that cold air is increasing instability in the atmosphere, weather officials said. Showers on Thursday and Friday could include thunderstorms, which have the chance to bring hail, downpours, small tornadoes and waterspouts — though that will be isolated, Wofford said.
Rain totals will mostly remain under half an inch, with some locally higher accumulations where thunderstorms occur.
Temperatures across Central California also are likely 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 late Wednesday and remain through Friday, with 6 to 12 inches of snow expected above 3,000 feet.
“Travel will be very difficult,” the warning said. “Strong winds could cause tree damage. Cold wind chill readings as low as 20 degrees below zero could cause frostbite on exposed skin in as little as 30 minutes.”
In the state’s northwestern corner, weather officials warned about subfreezing, “unseasonably cold” temperatures beginning late Wednesday, with snow falling as low at 1,500 feet and mountain temperatures dropping to 15 to 25 degrees.
