Which of the following describes a system that moves longitudinally with the polar front?

A system that moves longitudinally with the polar front is identified as migratory lows. These systems, also known as mid-latitude cyclones, form along the polar front where warm and cold air masses meet. They travel from west to east, following the general path of the polar front. This characteristic of moving longitudinally is crucial, as these systems are influenced by the temperature differences between the polar and tropical air masses, leading to the development of fronts and weather changes.

Trade Winds and prevailing westerlies are consistent wind patterns that generally flow in specific directions across the globe but do not directly describe the movement of weather systems. Monsoons are seasonal wind patterns that bring significant changes in precipitation and are not inherently linked to the longitudinal movement with the polar front. Thus, migratory lows represent the systems specifically associated with this phenomenon.