The first story in a radio newscast is the most important in a collection of stories read at the time you tune in. Usually that lead story is the most up-to-date, and appeals to the greatest number of listeners.
Think of the inverted pyramid which is wide at the top, emphasizing the big story. That pyramid narrows until it reaches the bottom where the newscast ends with a “kicker” story, usually a lighthearted good news item that is supposed to send listeners off with a smile. That’s what I was taught at school anyway.
A music radio station I worked for early in my career restructured that pyramid and instituted a “good news” policy whereby the top story needed to be a positive story.