Fronts

Fronts

Areas of high and low pressure are constantly moving across the Earth's surface, with air moving between them. Air moving into an area brings with it the characterists of where it has come from. Where two air masses with different characteristics meet, the air does not mix easily, but forms a boundary, called a front.
As winds circulate around a frontal depression, they bring warm air into an area where there is colder air and vice versa. This movement of air forms warm and cold fronts. [VH] {WC}