Which is the best explanation for how air masses move across the US?
which is the best explanation for how air masses move across the united states
Not necessarily. While cold air masses in the northern hemisphere often originate farther north than the areas they move into, they most often move westward, as they are usually brought in by westward-moving systems that rotate counterclockwise. In the southern hemisphere the air masses originate in the south and are associated with clockwise-rotating systems.