A total of 13 vote centers are open in San Diego's First Supervisorial District for the final day of voting to replace former San Diego County Supervisor Nora Vargas.

It's Election Day in the South Bay, whatever that means in a race where the vast majority of voters will cast a ballot by mail, and more than 50,000 people already have. Why it matters: It's the primary for the special election to fill the vacancy left by former Supervisor Nora Vargas' abrupt resignation last year.

The first returns in Tuesday’s special election for county supervisor show Chula Vista Mayor John McCann and Imperial Beach Mayor Paloma Aguirre in the lead to advance to a runoff later this year.