Trevor Ault reports on the massive, blinding dust storm – also known as a haboob – that swallowed Phoenix, knocking out power to thousands and even grounding flights, as monsoon rains swept in; Matt Gutman has details on pop star Taylor Swift and NFL star Travis Kelce announcing their engagement after dating for two years; Diane Sawyer sits down with Bruce Willis' wife, Emma Heming Willis, who opens up about her husband's deeply personal battle faced by so many families across the country, when a loved one faces down dementia – and the challenges they are overcoming together in the ABC special “Emma & Bruce Willis: The Unexpected Journey”; and more on tonight’s broadcast of World News Tonight with David Muir. 00:00 Intro 02:34 Massive dust storm sweeps through Phoenix metro area, leaving thousands without power 05:11 Below normal temperatures from the Rockies to the East Coast through Labor Day weekend 06:09 Trump moves to fire Fed Reserve Board Governor Lisa Cook, who refused to res...