A low-pressure weather system brought brief but heavy showers to the Bay Area early Thursday, with more rain expected on Sunday, a National Weather Service forecaster said.

Santa Rosa had the heaviest batch, with .43 inches of rain reported overnight as of 5 a.m., forecaster Diana Henderson said. Other areas of the region weren't soaked nearly as much, with San Francisco International Airport reporting .21 inches of rain, Oakland International Airport reporting .10 inches and the Norman Y. Mineta Airport in San Jose recording .09 inches.

Soggy roads made the morning commute a mess. Spinouts and fender benders plagued several Bay Area highways, and the wet weather was blamed for an injury wreck on northbound Interstate 880 near High Street in Oakland that blocked two lanes and backed up traffic for miles. In addition, some SFO flights were delayed nearly two hours due to this morning's showers, officials said.

The showers were expected to continue on and off through Thursday, with some clouds expected Friday and Saturday, though only occasional sprinkles are expected before more heavy rain arrives on Sunday, Henderson said.

The system was expected to drop about 2 inches of snow above 8,500 feet in the Sierra Nevada on Thursday afternoon. The snow level was expected to drop to 7,000 feet by Thursday night, Henderson said.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.