A low-pressure system is expected to sweep into Southern California Friday evening, bringing a chance of light precipitation in the Inland Empire this weekend, according to the National Weather Service.
The chance of measurable precipitation Friday has been set at 20 percent for the Riverside metropolitan area, but that will increase to 50 percent on Saturday, forecasters said.
Precipitation is not expected in the San Gorgonio Pass near Banning Friday, but there is a 40 percent chance of rain on Saturday, according to the NWS.
No rain is expected in the Coachella Valley this weekend.
The Riverside metropolitan area and the San Gorgonio Pass near Banning could get around one-tenth of an inch of rainfall Saturday while light snow could fall above 4,500 feet in the Riverside County mountains, NWS meteorologist Stephanie Sullivan said.
The storm system moving in from the north will bring a chance of light precipitation Friday evening into Saturday with another chance of mostly light precipitation late Sunday morning into Sunday night before the system exits the region by Monday morning, she said.
Rainfall rates this weekend will reach a quarter-inch an hour at the most so the risk of debris flows will be extremely low, Sullivan said.
Multiple neighborhoods in the Holy Fire burn area fell under mandatory evacuation orders at intervals between Jan. 31 and Saturday, when the last storm series produced heavy downpours, resulting in some downed power lines and a number of street closures. Mud and debris flows, however, did not cause any serious damage to residential properties.
A wide area skirting the eastern side of the national forest, bordering Lake Elsinore and the Temescal Valley, was left exposed to potential flood damage because of the 23,000-acre Holy Fire in August. The blaze, allegedly the work of an arsonist, denuded steep terrain below Santiago Peak, permitting water to flow unchecked onto lower slopes where subdivisions are situated.
High temperatures Friday are expected to reach 61 degrees in Riverside, 54 in the Riverside County mountains, 61 in the San Gorgonio Pass near Banning and 66 in the Coachella Valley.
Another storm system could bring precipitation Wednesday into Thursday, but there is still a lot of uncertainty about the timing of that system as well as how much precipitation it could bring, Sullivan said.