Slow-moving systems often form when a low-pressure area becomes detached from the jet stream, a fast-moving current of air high in the atmosphere. This detachment, known as a 'cutoff,' allows the system to remain stationary or move very slowly. Factors like temperature differences between land and sea can also influence the system's behavior, although not all slow-moving systems meet the criteria to be classified as nor’easters or other specific types of storms.