Southern California is experiencing the calm before the storm. Forecasters say a strong system is headed our way and, starting Sunday, poses the threat of thunderstorms, flooding, gusty winds and dangerous waves.
But before that happens, the region will have a warm, dry weekend. An offshore flow is pushing its way through the Los Angeles area Thursday into Friday, bringing sunny skies, according to Ryan Kittell, a meterologist with the National Weather Service’s Oxnard office.
There will be a slight drop in temperatures Saturday before a more significant change Sunday night. Heavy rainfall is expected, persisting into Monday as the storm makes its way across the region.
The strongest part of the storm system is set to land late Sunday through Monday, and those are the days meteorologists are most concerned about, Kittell said.
During that time, there is the potential for brief thunderstorms. Even a 15-minute burst of heavy rain can cause a debris flow, a concern in recent burn scar areas, said Carol Ciliderti, a meterologist with the weather service’s Oxnard office.
Through Tuesday, heavy bursts of rain, severe thunderstorms and damaging wind gusts are possible. By Tuesday night, meterologists say, rainfall will lessen, with on-and-off precipitation. Wednesday there will be a small break in the storm activity, but the rainfall is expected to pick back up Wednesday night through Friday.
“We have a high confidence that all areas will at least receive moderate rain amounts, intensities and totals, as well as some mountain snow, moderate mountain snow accumulations, at least at resort levels and possibly lower as we get deeper into the week,” Kittell said.
On Monday, Southern California coastal and valley areas will receive at least 1 to 2 inches of rain and twice that in the mountains, forecasters say.
Snow levels early in the week should remain above 6,000 feet for most of the storm’s duration, but significant snow could accumulate in the higher elevations.
Forecasters are predicting moderate effects from the storm including increased traffic accidents because of slick and flooded roads, minor mudslides and minor debris flow.
An advisory has not been issued for Southern California beaches yet, but forecasters say there is a strong chance that a high-surf advisory will be issued Monday to Thursday as a combination of southwesterly and west-northwesterly swells arrive along the coastline.
Wave sets above 10 feet will be possible across all Southern California beaches, and there is a 20% to 30% chance of damaging sets developing from Tuesday night through Wednesday night. The highest waves are predicted for the northwest-facing shores along the Central Coast.
The Bay Area’s coastline already is bracing for impact with a beach hazard warning in effect Thursday night through Saturday morning. Officials are alerting coastal communities of an increased risk for large waves and strong rip currents with breaking waves of 14 to 19 feet.
The Bay Area also will be hit with gusts of wind exceeding 40 miles per hour in Big Sur and areas of higher terrain Sunday. Intermittent periods of rainfall will drop the same day.
Although heavy rains are expected, Kittell said this storm system won’t be as severe as the storm last Christmas that set daily rainfall records around the region.
That so-called Pineapple Express was forecast to be the strongest atmospheric river storm to hit Southern California in nearly two years, according to the National Weather Service. It caused a days-long flood watch and evacuation warnings in burn scar areas.