I think God’s omnipotence is more complex than clairvoyance. God sees into our hearts and minds. He knows exactly how sincere we are. If he can see clearly into our souls, then he can easily judge our decisions and fate. Remember, as others have stated on this thread, the future is not a “real” tangible place. It doesn’t exist. As Saint Augustine said,
“How can the past and future be, when the past no longer is, and the future is not yet? As for the present, if it were always present and never moved on to become the past, it would not be time, but eternity.”
The future is directly related to now. For instance, I type this sentence in the present. This sentence that follows it is the future, it has developed from the “present” sentence, which is has now become the past. God exists in the eternity Augustine speaks about. He is the “Word”, never changing, never drifting into the future and becoming past. When he looks on from eternity at us, we are ever-changing, going from young to middle-aged to old. But the decision to follow his will and change our hearts and mind against sin is not an earthly one. It is an eternal one. When God looks at us, he sees our whole lives, from the past to the present, extending in time, this extension filling the future. If we decide sincerely to follow his will, and make an effort to change our lives to please and serve Him, this decision will echo throughout all of these stages, and will counterbalance the decisions we make that are against His will.
It’s not that God sees into the future. It’s that he can see your present decisions, compare them to the past, and then predict the future based on this knowledge. When it comes judgement, we will all have to account for our sins, but hell is only for those who reject God’s will and love entirely. Let’s suppose you have sincerely tried to live your life according to His will, and have a bad day, but are deeply repentant about your fall. God is merciful. If you are sincerely repentant, He will see this fall in the context of your past efforts to change. God is eternal, his will corresponds best with the present.The fall will become past immediately after it is committed, and your repentance will become present. This why the Sacrament of Reconciliation is important. This is why Jesus said, “Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.” ( Mathew 5-7, 34). It is also why, after forgiving sinners, He said, " Go, and sin no more." If you sincerely turn against sin in each present moment, your past sins will be reconciled, and your future will be shaped by this aversion to sin. If you live in the moment, you will be more in tune with God, because your life will be patterned on a constant vigilance to sin in the present, and therefore closer to an favorable eternal judgement.
This is all speculation, of course.