California bomb cyclone storm: When will rains hit L.A. area and how bad will it be?

Northern California is being hit hard by the first major atmospheric river storm of the season, with rain totals expected to exceed 12 inches in some areas, bringing a chance for flooding and mudslides.

The effects in Southern California of the so-called bomb cyclone storm, which describes how rapidly the storm strengthened in the Pacific before it moved onshore, will be less dramatic, but forecasters are saying some rain is likely by the weekend, though how much isn’t clear.

Here is what we know:

Forecast

In Southern California, the chances for rain have been steadily increasing as the system advances, with forecasters now confident that the region could see measurable amounts beginning this weekend and into early next week.

Friday: Rain begins in San Luis Obispo County.

Saturday: Rains hit Los Angeles and Ventura counties in the morning and through the evening.

Next week: A chance of rain Sunday through Wednesday, but forecast remains in flux.

California

California’s rainy season begins with a bomb cyclone bang. Are we in for a third record wet winter?

The first major atmospheric river system is pummeling the Pacific Northwest and Northern California, supercharged by a bomb cyclone. But officials still say it’s too early to determine what the rest of the winter could bring.

Nov. 20, 2024

Conditions

On Saturday, Los Angeles and Ventura counties could see anywhere from a tenth to a third of an inch of rain. San Luis Obispo and Santa Barbara counties could see up to an inch in some areas.

Fire risk

The storm comes just two weeks after the Mountain fire destroyed or damaged more than 350 homes in Ventura County. That fire was fueled by dry conditions and intense Santa Ana winds.

“We’re thinking it’s going to be more of a beneficial rain,” said Bryan Lewis, a National Weather Service meteorologist in Oxnard. He noted this weekend’s rain could help ease some fire concerns, but likely will not eliminate those worries entirely.

Longer-term trends

Through at least the end of the month, the National Weather Service’s Climate Prediction Center is forecasting an increased chance for above-average rainfall across much of California, but predictions stretching into mid-December become less clear. The latest three-month outlook through January shows equal chances for above or below normal precipitation.