UPDATE 5 P.M.: The National Weather Service lifted its flood advisory for San Luis Obispo County at 4:56 p.m.
Forecasters say scattered showers will continue through Saturday evening, with the threat of an isolated thunderstorm.
The Weather Service said that widespread rain rates of one tenth of an inch, and isolated instance of up to a quarter of an inch, of rain will continue this evening.
They also warn of ponding on roads that could make driving conditions tricky.
The National Weather Service office in Oxnard issued an urban and small-stream flood advisory at 2:28 p.m. for central San Luis Obispo County, including the city of San Luis Obispo through 5:15 p.m.
Forecasters note that a strong system of showers and thunderstorms - which has produced moderate to heavy rain - could cause flooding in small creaks and streams, as well as low-lying areas.
Excessive runoff from heavy rains will cause higher water levels in small creeks and streams, as well as ponding in urban locations such as highways, streets, underpasses and intersections, according to the Weather Service.
Flooding could also take place in areas with poor drainage and low-lying locations, forecasters warn.
The storm could also produce small hail over the San Luis Obispo area, forecasters warn. They added that rainfall gauges have shown that rain is falling at a rate of more than one inch per hour in some locations. Noting that most flood deaths take place in vehicles, the Weather Service cautions never to drive into areas where water is covering the road, because flood waters are usually deeper than they appear.
Just one foot of flowing water is powerful enough to sweep a vehicle off the road, the Weather Service warns.