A powerful winter storm will soak Los Angeles and much of Southern California on Monday, dampening plans for Presidents Day and threatening thunderstorms and possible flooding through midweek.
“This is a storm with a lot of energy,” said Rose Schoenfeld, a meteorologist with the National Weather Service. “There’s 30% to 40% chance of thunderstorms on Monday. We could see damaging wind gusts, intense rainfall, water spouts or brief, weak tornadoes.”
Though it’s expected to start drizzling overnight, Angelenos likely won’t see heavy rainfall until late Monday afternoon, with showers predicted through the evening. The coasts could see 1 to 2½ inches of rain, with up to 5 inches predicted for the foothills and mountains.
A colder, weaker storm will sweep in Tuesday night into Wednesday, forecasters said, dumping an additional inch to inch and a half of rain on the coast and up to 3 inches more in the foothills. Similar conditions are expected across much of Southern California.
“Monday is really the day to watch,” Schoenfeld said.
Presidents Day will also bring heavy snow to Northern California and the Eastern Sierra, with several feet predicted in the mountains and whiteout conditions near Mammoth and Lake Tahoe.
Most of Los Angeles will be under a flood watch until at least 9 p.m. Monday, with “a 20% chance of more damaging debris flows in burn scar areas,” Schoenfeld said.
Residents near the burn scars from last year’s firestorm will remain under an evacuation warning through Tuesday. Portions of Topanga Canyon Boulevard were closed beginning at 10 p.m. Sunday and extending into midweek.
“All Angelenos — especially those in burn scar areas — are encouraged to follow official guidance, use caution on the roads, plan ahead, and stay informed,” Mayor Karen Bass said in a statement.
Bass and other officials warned Angelenos to stay inside and off the roads as much as possible.
“I want to urge residents to take this forecast seriously and prepare now,” L.A. County Supervisor Hilda L. Solis said in a statement Sunday. “While this storm is not expected to be as intense as the atmospheric river we experienced in December, heavy rain, thunderstorms, and dangerous surf can still create serious hazards, including flooding and debris flows.”
Hail and lightning are also possible, though less likely, Schoenfeld said.
“We want to emphasize that the conditions will be extremely unfavorable for hiking, camping, driving out into the mountains,” Schoenfeld said. “Mountains will be a very dangerous place to be during these storms.”
Snow is expected to blanket parts of Southern California through Wednesday, with up to 3 feet predicted at the highest peaks and a dusting possible across the Interstate 5 corridor.
Travelers on the Grapevine could see “blowing snow and near whiteout conditions,” Schoenfeld said.
“We have ‘Operation Snowflake’ activated on I-5 through Tejon Pass,” said Coleen Park, a public information officer with CalTrans District 7. The alert system puts in place precautions including around-the-clock maintenance of the roadway and possible closure and detours around the Grapevine.
“We do ask people if they have to be on the roads, then prepare for emergencies,” Park said.
Flurries will also blanket Big Bear, where several feet of snow could fall through Wednesday.
Despite a wet and wintry start to the week, Angelenos can expect sunshine and mostly clear skies by late Thursday, with temperatures climbing back into the low 70s over the weekend.
