Scattered showers will persist into the weekend with a chance of flooding, the National Weather Service said Friday, and the Department of Environmental Health issued a general rain advisory for coastal waters of San Diego County.
Forecasters predicted cooler weather, a chance of showers and a slight chance of thunderstorms through Friday night, as well as a slight chance of showers Saturday throughout San Diego County.
A flash flood watch for the mountains and deserts will remain in effect from noon through Friday evening.
"Bands of heavier showers and isolated thunderstorms could cause local small stream flooding with isolated flash flooding possible," the weather service said.
Swimmers, surfers and other ocean users are warned that levels of bacteria can rise significantly in ocean and bay waters, especially near storm drains, creeks, rivers and lagoon outlets that discharge urban runoff.
Urban runoff can contain large amounts of bacteria from a variety of sources such as animal waste, soil and decomposing vegetation. While many coastal storm drains within San Diego County are permanently posted with white metal warning signs, additional temporary warning signs are not posted for general advisories.
Activities such as swimming, surfing and diving should be avoided in all coastal waters for 72 hours following rain. This includes all coastal beaches and all of Mission Bay and San Diego Bay.
Elevated bacteria levels can persist after a rainstorm depending on the intensity of the storm, volume of runoff and ocean and current conditions.
In addition, a water contact closure has been issued for Tijuana Slough National Wildlife Refuge and Border Field State Park.
The Department of Environmental Health issued the water contact closure for the ocean shoreline at the Tijuana Slough National Wildlife Refuge and Border Field State Park due to sewage-contaminated flows from the Tijuana River entering the United States.
The closure area includes the beach line from the south end of Seacoast Drive to the International Border.
Signs will remain in place until sample results indicate the ocean water is safe for recreational use.
