CLASSIFICATION OF FRONTS
Fronts can be classified geographically and also according to the motion of the air masses involved.
The diagram shows a typical cold front and its weather map symbol. Similar to the warm front, the steeper the slope of the front, the more violent are the storms associated with it. The width of the front is usually 50-100 km; however, on the scale of the diagrams, it looks like a line.
Further differentiation of cold fronts on the basis of vertical velocities is shown in two types. Type I cold fronts are those observed outside the zone of cyclonic activity and are generally slow moving which may even be quasi-stationary in some cases. It is defined by a general upglide of warm air over the entire frontal surface so that the cloud system resembles that of a warm front. Type II cold fronts are observed within the zone of cyclonic activity and as a rule move very rapidly. Warm air is lifted only along the leading edge of the intruding wedge of cold air. At higher levels, the warm air is moving faster than the cold air and therefore no ascending motions are observed in the warm air above the frontal surface.
A warm front and its weather map symbol is shown in the diagram.
A stationary front forms when two air masses remain over a region for several days. The front formed does not move.
The weather at the occluded front is long, steady rain - similar to warm front weather. Sometimes the front ends with sharper cold front storms. The map symbol is shown in the left diagram.
During the winter months in the northern hemisphere, cold fronts usually extend to as far as the southern portion of the Philippines. They are responsible for some of the rainfall along the eastern coasts of the country.