Kauaʻi and Niʻihau are expected to experience tropical storm-force winds of 39 mph (63 km/h) or higher starting Monday afternoon, with gusts potentially exceeding 60 mph (97 km/h) in some areas. Heavy rainfall, with over a foot (30 cm) possible in interior mountain regions of Kauaʻi, could lead to flash flooding and mudslides. Coastal areas on south and west-facing shores may see damaging surf reaching heights of 20 to 30 feet (6 to 9 meters) and coastal inundation of 1 to 3 feet (0.3 to 0.9 meters). Additionally, there is a risk of fast-moving waterspouts and tornadoes in the rainbands near Kauaʻi and Niʻihau on Monday and Monday night.