Board Thread:TV Show Discussion/@comment-27612062-20160114231122/@comment-5014364-20160206214013

Yes and no; the novels address this. The thing is that Melisandre does have magical powers, specifically prophetic powers...but she doesn't have nearly as much control over them as she lets people think she does. In the fifth novel she actually becomes a POV narrator (briefly), and her chapters give the insight that she's basically playing up the whole "mystical prophet" thing because it helps over-awe people (the TV show did mention this a bit when she's explaining to Selyse that she enhances her bonfires with pyrotechnics and such).

As with many prophecies, she gets stuff wrong, even to her own surprise. She only sees vague and confusing images in her flames, and tries to put together what they prophecy - sometimes with reasonable accuracy, to be sure, but other times not.

For example, in the novels when she's at the Wall and Stannis is on campaign going south (she stays at the Wall in the books), and no one knows what's happening to him due to the snowstorm, she looks into her flames and beseeches the Lord of Light to show her a vision of the Prince Who Was Promised. Melisandre looks into the flames, but all she sees is snow.