After hammering Mexico's Yucatan Peninsula as a tropical storm, Whit Johnson has the latest on the emergency preparations underway in Florida for Hurricane Helene, and Ginger Zee tracks the system, which is forecast to grow into a Category 4 hurricane when it makes landfall; Melissa Adan reports on the bomb that officials say exploded inside a Santa Maria, California courthouse, injuring several people; Matt Gutman has details on the Los Angeles bus hijacking that turned deadly after a gunman shot a passenger multiple times; and more on tonight's broadcast of World News Tonight with David Muir.