When two large air masses meet, the boundary that separates them is called a front. Fronts represent fairly abrupt transitions between two large air masses. This means that when two different bodies of air come together, they do not readily mix. Rather, each body of air will retain its individual properties, and a boundary forms between them.
Types of Fronts:-
Warm Fronts: A warm front occurs when a warm air mass advances and replaces a cold air mass. On a weather map, a warm front is depicted as a red arc, with red semicircles pointing in the direction of the advancing warm air.
Cold Fronts :-A cold front occurs when a mass of cold air advances into a region of warmer air.
Stationary Fronts:- A stationary front forms when a cold front or warm front stops moving. This happens when two masses of air are pushing against each other but neither is powerful enough to move the other. Winds blowing parallel to the front instead of perpendicular can help it stay in place.
Occluded Fronts:- Sometimes a cold front follows right behind a warm front. A warm air mass pushes into a colder air mass (the warm front) and then another cold air mass pushes into the warm air mass (the cold front). Because cold fronts move faster, the cold front is likely to overtake the warm front. This is known as an occluded front