The immediate risks include heavy rainfall, flooding, and landslides in southwestern Mexico as Polo strengthens into a hurricane. In Southern California, the storm could lead to increased humidity and high surf, potentially exacerbating coastal erosion in areas already affected by previous storms. Vulnerable coastlines, such as those in Laguna Beach and Carlsbad, may face further sand loss and damage. The exact impact on California remains uncertain and depends on atmospheric patterns and the storm's track.