The first big storm of 2020 for Southern California is expected to drench the region and bring mountain snow to lower elevations on Thursday, potentially leading to road closures and traffic delays, according to the National Weather Service.
A fast-moving frontal system will likely cross into the region Thursday afternoon, bringing with it the first significant rain in nearly three weeks.
“If we get rain on Thursday [downtown], that would be about a 20-day rain pause or hiatus since the light rain on Dec. 26,” Bill Patzert, former climatologist at NASA’s Jet Propulsion Laboratory, told the Los Angeles Times.
Coastal and valley areas can anticipate a quarter to three-quarter inches of rain, while mountains and foothills may get as much as 1 1/2 inches, forecasters said.
NWS warned of wet afternoon and evening rush-hour commutes that could be impacted by potential minor urban and roadway flooding.
Storm coming Thursday and Thursday night. Significant roadway impacts expected. I-5 Grapevine could have snow delays or closures. Bring chains, food and blankets if you must travel in the mountains. Wet urban roads will cause delays for evening commute. #BeSafe #Cawx #LARain pic.twitter.com/cj3n84eXQp
— NWS Los Angeles (@NWSLosAngeles) January 14, 2020
Mountain road closures are also possible as snow levels plummet to between 3,500 and 4,500 feet. That could affect the 5 Freeway along the Grapevine, as well as state routes 2 and 33, according to the weather service.
Up to 4 inches of snow is possible at elevations as low as 3,500 feet. Areas above 5,000 feet could receive 4 to 8 inches of snow, forecasters said.
Anyone traveling through the mountains on Thursday is urged to bring chains, food and blankets with them.
The storm is expected to linger through the night before drier weather returns once more — this time likely lasting through the rest of the month, according to Patzert.
“January is looking like a dud,” he said.
Updated information on the next system Thursday/Thursday night. Snow is expected mainly over the mountains of San Bernardino and Riverside Counties (snow levels around 5000 feet). Light to moderate rain will impact areas below 5000 feet. Strong winds mountains/deserts. #cawx pic.twitter.com/qAWFbTQnet
— NWS San Diego (@NWSSanDiego) January 15, 2020
Satellite imagery shows a strong storm developing off the West Coast early this morning. This system will bring a variety of inclement weather to #NorCal later today into early Friday. #CAwx pic.twitter.com/kwsuAuplSe
— NWS Sacramento (@NWSSacramento) January 15, 2020