Sandburg's Fog

To me it seems like he is comparing for to the cat. When he states that the fog comes on little cat feet it seems like he is talking about it creeping up as a cat would it's prey. While the fog sits it's like the cat is setting there mid prowl watching his target and observing. As the fog moves on it's as if the cat's prey either got away and the cat continues like nothing happened or like when after a cat catches his prey and is done playing with it or eating it the cat just leaves what is left lying there and continues on with it's life like nothing happened. I suppose this could be related to other things in life. I think it could also compare to love. When you do finally find love it creeps up on you like the fog. If things go bad and you break up then it sets there for a while and you feel in the dumps and it slowly fades away, as fog does, and you move on to the next thing like fog would move to the next city.