Fronts

The most common definition of a front is a “boundary between dissimilar air masses.” While this boundary is typically manifested as a thermal discontinuity, in some cases a moisture discontinuity can also behave as a front. In the plains of the United States, this moisture discontinuity is commonly referred to as a dryline, separating continental tropical and maritime tropical air masses.

The classic definition of a front, which implies a sharp zero-order boundary, often leads to a misunderstanding of its concept and structure. A front is actually a human construct considered to represent the leading edge of a strong thermal gradient. As a result, it is very difficult to find consistency in its placement on weather maps, even by professional meteorologists. This is especially true with ...