Tropical Storm Melissa lumbered through the Caribbean Sea on Thursday, bringing a risk of dangerous landslides and life-threatening flooding to Jamaica and southern Hispaniola. Officials urged residents of flood-prone areas to seek higher ground. The storm was blamed for downing a large tree that killed an elderly man in the coastal town of Marigot in southern Haiti, while five other people were injured in flooding in the central Artibonite area, according to the Civil Protection Agency.