I have really enjoyed the book The God Delusion by Richard Dawkins so far. I read this over a few times.
If God is omniscient, he must already know how he is going to intervene to change the course of history using his omnipotence. But that means he can’t change his mind about his intervention, which means he is not omnipotent.
If you believe that God preordained everything from the beginning then there is no need for Him to change His mind. I’m sure that point will be addressed as I continue reading.