How do I turn off CNN news notifications?

Since I upgraded my iMac to El Capitan I have been receiving banner notifications in the upper righthand corner. This does not bother me when I am hearing about computer updates, email messages, and stuff of that nature. However, I despise working offline and suddenly having some obnoxious news headline suddenly pop up over my work. If I want to see the news, I will go online and look, not have it shoved down my throat. Unfortunately, the only settings I can find in notifications turn everything off. I don't want to turn ALL notifications off, just the invasive CNN newsfeed. Is there a way to do this?