"For the general public, it's a good idea to move Friday," Bloomberg said. "Keep in mind, it is possible--I don't know that I want to say likely--but it is very conceivable…that Saturday morning at 8 o'clock, we're going to say, 'Look, the forecast has not changed. The storm is still barreling down on us. It's still very dangerous. You must get out of these areas.'"