Here's my theory:
Christ's incarnation existed in an instant in time. By taking on physical properties, Christ was not "omnipresent" during his sojurn on earth. The Father and The Holy Spirit remained in "eternity" and thus were possessed with all knowledge and all power. When Christ said that he only knew what the Father revealed to him, was he telling the truth? When Jesus said that he did not know the day or the hour of his return, was he telling the truth?
So the question is why, at that moment "in time" did Christ not know the future? Because at that moment he was dewelling "in time" and not in eternity. Thus he could not independently know the future, because from his point of view, it had not yet happened. But from the Father's point of view, from the eternity point of view, the future was certain because the Father was there and the Father knew it.
What's your theory?