The Hawaiian Islands are at risk of significant rainfall, with totals ranging from 5 to 10 inches (13 to 25 centimeters) and localized amounts up to 20 inches (51 centimeters). This could lead to flooding and mudslides, particularly in vulnerable areas. High winds and dangerous surf conditions are also expected, posing risks to coastal and low-lying regions. While Tropical Storm Hernan is not currently a threat to land, the potential Tropical Cyclone One-C could have a direct impact on Hawaii's Big Island.