According to the poet, in what respect is the fog similar to a cat? Do you think the comparison made is appropriate?

The poet Carl Sandburg observes the analogy between the fog and the behaviour of a cat. The approach of the fog is silent and noiseless, stealthily advancing on its silent, ‘paws’. From a distance, it seems like a cat moving on its haunches cautiously, analysing its surroundings before being taken into notice.