The primary risk from Tropical Storm Arthur is heavy rainfall leading to flash flooding, which could pose a danger to life and property. Areas in Louisiana and Mississippi are already experiencing rain rates of up to 3 inches per hour, causing localized flooding and power outages. The storm's impact extends beyond the southeastern US, with strong winds and possible tornadoes reported in the Midwest, including Illinois and Kentucky. Damage to homes, downed power lines, and blocked roads have been reported in affected areas. Over 130,000 homes and businesses in the Midwest are without power as of Thursday afternoon.