Snow, wind and the heaviest rain event of the season is expected this week in portions of Southern California. Rain is expected to arrive early Wednesday through Saturday morning.
San Diego, California – Southern California is bracing for what meteorologists are calling a “significant” atmospheric river event — the kind of storm that can rewrite a city’s relationship with water in a matter of hours. Forecasters say the region could see an entire month’s worth of rain between Thursday and Saturday, triggering fears of flash floods, mudslides, and power outages across the state.
The National Weather Service warned Wednesday that the incoming system could bring between 1 and 2 inches of rain across much of the state, with certain mountain areas seeing more than 3 inches. In Los Angeles, roughly 1.3 inches are expected — nearly the city’s entire November average, packed into three days.
“It’s anomalous, but not unheard of,” said Bob Oravec, lead forecaster with the NWS Weather Prediction Center. “Especially across an area that has a large standard deviation year to year with respect to precipitation. The average doesn’t necessarily reflect what they typically get.”
The culprit is what scientists call an atmospheric river — a long, narrow current of moisture that forms over the Pacific Ocean and carries immense amounts of water vapor toward the coast. The National Oceanic and Atmospheric Administration likens them to “rivers in the sky.” These systems are a double-edged sword: essential to California’s water supply, yet capable of producing some of its most destructive floods.
The storm’s timing is unusual. While atmospheric rivers are common in California, they usually arrive during the heart of winter, between December and February. This one, arriving in early November, is hitting far earlier — and farther south — than typical. “It’s a bit early for one to reach this far down the coast,” Oravec said, “but the conditions are lining up.”
Rain is expected to begin along the Central Coast — in San Luis Obispo and Santa Barbara counties — late Thursday before sliding south into Los Angeles County by Friday. The heaviest rainfall will likely hit Friday night into Saturday, with the potential for isolated thunderstorms.
Weather models suggest that the system could stall offshore, prolonging the storm over Southern California. “Forecasted rainfall amounts have dramatically increased to 1.5 to 3 inches for Southern California this weekend,” wrote extreme weather chaser Colin McCarthy on X. “It will end fire season across the region.”
The region’s wettest months are still ahead, but this storm could serve as an early warning: California’s climate, already stretched thin between extremes of fire and flood, is now blurring the boundaries of its seasons. Or, as the skies over Los Angeles are about to remind everyone, there’s no such thing as normal weather here anymore.
