Days of soggy weather on the way for Los Angeles as atmospheric river looms

Don’t stow those umbrellas and raincoats quite yet, Angelenos, because more soggy weather is on the horizon.

A brief drying-out period has followed last week’s strong storm, which brought record rainfall and dumped snow on mountains and high deserts. But it’s expected to give way to even more rain across Southern California through Wednesday. Then another storm should arrive in time for the weekend.

An atmospheric river, swelled with subtropical moisture that’s sweeping in from the west, is expected to move down along the Central Coast by late Monday, with precipitation of up to 4 inches in the region north of Morro Bay. By the time the storm front reaches Los Angeles early Wednesday, it is expected to weaken slightly, meaning Southern Californians will see a bit less rain than their neighbors to the north, said Lisa Phillips, a meteorologist with the National Weather Service in Oxnard.

“Off the coast of Northern and Central California, we do have a pretty good moisture connection that’s bringing a good deal of rain to the Central Coast,” she said. “By the time it pushes through that whole area and reaches southern areas, it’s weaker.”

The storm was dumping rain on Northern California on Monday, resulting in downpours that caused some localized flooding in the Bay Area, officials said.

A portion of the Santa Lucia Mountains in Monterey County received more than a foot of rain in about 36 hours from the storm, said Matt Mehle, a meteorologist with the National Weather Service in San Francisco.

“That’s not uncommon for a winter event,” he said, “but it’s certainly an impressive amount of rainfall.”

The storm will bring periods of moderate to possibly heavy rain to much of Los Angeles County by early Wednesday. Rainfall totals of 1 to 2 inches are expected for much of the region, but the San Gabriel Mountains could see up to 3 inches of precipitation. Rainfall rates could exceed half an inch per hour in some areas, which could cause minor mud and debris flows for recent burn areas, according to the National Weather Service.

This system is also significantly warmer than last week’s storm, which plummeted snow levels to 1,500 feet, blanketing mountain ranges and the Antelope Valley region of Palmdale with fresh powder. Snow levels with this storm are expected to linger around 6,000 to 7,000 feet, but heavy rain and snow melt could cause flooding in the mountains, the weather service warned.

“We’re on the rainfall convoy here,” said former Jet Propulsion Laboratory climatologist Bill Patzert. “After an exceptionally dry eight months, the rain may have ruined a few Thanksgivings, but the big picture is it’s pretty welcome in California.”

The much-needed moisture has dropped fire danger to normal levels across the Southland. Although the potential for large fires has lessened, a report from the National Interagency Fire Center released Sunday warns that there are still a few dry areas across the state that could burn if late-season Santa Ana winds kick up.

Long-term models suggest the southern section of the state should expect overall warmer and drier conditions than average through March, the report states. Officials with the National Oceanic and Atmospheric Administration also predict drier-than-normal weather from December through February across much of the state, save for a small portion of Northern California near the Oregon border.

Patzert said, however, the long-term models should be taken with a grain of salt. It’s a little too early to tell with much certainty what Mother Nature has in store for California this winter, he said.

“This atmospheric river is not necessarily a guaranteed precursor to rain this season,” Patzert said. “What we know for sure is November started out like a lamb and went out like a lion in the West.”