Heavy rainfall moved through Southern California early Saturday morning as part of a wet day in the region, bringing potentially dangerous conditions as flood warnings go into effect.

Between one and three inches of rain was expected for low-elevation Southern California communities between Saturday and Sunday, according to the National Weather Service.

“If you’re just waking up to this, just know there is very heavy rain to come,” said KTLA meteorologist Kacey Montoya.

Thunderstorms are a possibility for Saturday, bringing along a flash flood warning in Los Angeles County. The heavy rain over a small period could bring urban flooding as drainage systems may not be able to keep up with the flow.

“Those who do see those thunderstorms, you’re going to see very heavy rainfall in a short amount of time which has the likelihood to cause some flooding,” Montoya said.

Rain was expected to taper off in the Los Angeles area by 9 a.m. as the storm travels south. In the Inland Empire and Orange County, some drying should occur by the afternoon.

The Grapevine and other mountain areas between 6,000 and 7,500 feet in elevation could see up to three feet of snow, according to the NWS, and higher elevations could receive even more.