Important details can come and go quickly. Decisions are made and direction given, but without proper communication throughout the team, inevitably something will be dropped.
Sometimes we want to wait until a cohesive plan, beginning to end, is formed and in place. But by that time, deadlines are too close to accomplish with excellence.
Communicate before you feel it's necessary and before you feel ready. An informed team can begin running with you instead of sitting on the sidelines.