Southern California is expected to finally receive some rainfall beginning this weekend, meteorologists said Friday, with on-and-off showers bringing up to an inch and a half in some areas, spread out over three days.

Rain could begin as early as this afternoon in Los Angeles, but most will probably fall Sunday night and into Monday, meteorologist Kristan Lund said.

“We’re looking at about half an inch to an inch of rain for Los Angeles and Ventura counties, with an inch to 2 inches possible in the mountains and foothills,” Lund said.

Temperatures will drop significantly as the cold storm system moves into the area. Today will see highs in the low 60s across the county that will progressively drop into the high 50s.

The wet weather would be good news for firefighters battling Los Angeles County fires, but the rainfall could bring problems, too.

There is a 10-20% chance of thunderstorms, which could be dangerous in the wake of recent wildfires. If a thunderstorm occurs and happens to line up with one of the fire-scarred areas, there’s risk of a debris flow.

“The ground is hydrophobic after a fire,” Lund said. “Water sits on top of the land and floats all of the debris, the trees, structure debris, ash.”

However, meteorologists don’t expect this weather system to bring enough rain to cause debris flows or mudslides.

In the Palisades fire’s footprint, Malibu is looking at an inch of precipitation over the course of the weekend and into Monday.

In the Castaic area, where the Hughes fire has raged, the expected rain will be a welcome aid to firefighters. That area is expected to get an inch over a few days.

Of the three recent major fires, the Eaton blaze’s burn print presents the most at risk this weekend due to its proximity to the mountains. However, prediction models suggest that Altadena will receive only slightly more rainfall than Malibu.

Regardless, it’s still a concern for the area where workers are sifting through the remnants of thousands of destroyed structures.

Debris cleanup was underway this week, with the focus on removing hazardous materials in the Palisades and Eaton fire areas, as well as clearing sediment and debris from flood-control dams and debris basins.

Orange County and the Inland Empire are expected to see a similar drop in temperatures this weekend. Highs will be in the mid- to low 60s across that region today, dropping down to mid 50s by Monday.

Orange, Riverside and San Bernardino counties will receive rain as well this weekend, perhaps one-half to three-quarters of an inch between Saturday and Monday to most areas, meteorologist Adam Roser said.

Some valley locations could see slightly over an inch, while mountain regions may receive up to 2 inches.

Riverside and San Bernardino counties, however, may end up seeing amounts on the lower side, due to mountains in Orange County creating a rain shadow, Roser said.

The San Bernardino County Fire Department posted a warning to homeowners on social media ahead of the expected rain: They were urged to take precautions such as having an emergency plan in place, assembling a disaster kit, clearing nearby gutters and drainage systems, and using sandbags to divert water from their homes.

“We are looking out for our first chance at what could be some measurable rainfall,” department spokesperson Eric Sherwin said.

“That being said, we aren’t expecting it to fall in amounts or at rates that will result in mud or debris flows. We’re taking this storm as a reminder for those that live in areas prone to mud or debris flows, to make sure you have a plan.”

The National Weather Service also issued a winter storm warning beginning at 4 p.m. today and lasting until 4 p.m. Monday for San Bernardino County mountains, including the towns of Wrightwood, Big Bear Lake, Crestline, Running Springs and Lake Arrowhead.

It anticipates 12 to 18 inches of snow above 6,000 feet and 3 to 6 inches above 4,000 feet.

“Roads, and especially bridges and overpasses, will likely become slick and hazardous,” the weather service said on its website. “If travel is absolutely necessary, drive with caution and be prepared for sudden changes in visibility.”