Atmospheric river aimed at SoCal: Flooding alerts for millions, thanks to El Niño
The winter season's first significant storm is set to wallop southern California over the next few days, bringing heavy rain and the threat of flooding to millions of people. In addition, forecasters warned that mudslides and power outages are also possible.
This will be the area's first El-Niño influenced storm, one that's fueled by an atmospheric river of moisture, the National Weather Service said. It's expected to be the biggest rainstorm for the region since Hurricane Hilary dumped up to half a foot of rain in August, AccuWeather forecasters said.
In all, some 22 million people live where a flood watch is in effect, including most of the Los Angeles and San Diego metro areas.
When will the storm hit?
Although some light rain will begin late Tuesday and continue into Wednesday, the heaviest and steadiest rain around Los Angeles is likely on Thursday and around San Diego from Thursday night to Friday, AccuWeather meteorologist Alex Sosnowski said.
A prolonged period of heavy rain will develop over southern CA Wed-Thu as a deep upper low approaches the coast. Rain may be locally heavy at times, & numerous floods are likely. Flash & urban flooding are expected, & debris/mud flows will be possible. Turn around, don't drown! pic.twitter.com/5Hf5UJYKlD
— NWS Weather Prediction Center (@NWSWPC) December 19, 2023
Will it be rain or snow?
The weather service said that since temperatures are fairly mild, "rain will be the primary precipitation type associated with this system," except that snow is expected over the higher elevations along the Sierra Nevada. A winter storm warning is in effect for the highest elevations of the Sierra, which will see "dangerous or nearly impossible driving conditions," the weather service said.
How much rain will fall?
"Downtown Los Angeles has a good chance to pick up 2 inches of rain or more from the storm during the second half of this week," AccuWeather meteorologist Alan Douty said. He added that heavier rain is likely to fall on the west- and southwest-facing slopes of the Coast Ranges, with perhaps two to three times the amount that drenches the Los Angeles basin.
David Sweet, a meteorologist with the weather service in Oxnard, California, said those traveling in the area on Wednesday and Thursday should allow more time to get to their destinations, he said.
“Roads will be wet. There will be ponding of water on the roads,” Sweet said. “To avoid accidents, people need to slow down and drive with a great deal more caution.”
Contributing: Cheri Carlson, The Ventura County Star
This article originally appeared on USA TODAY: El Niño-fueled atmospheric river storm forecast to wallop California
