Figure 3-17.Occluded Front

CHAPTER THREE

AVIATION WEATHER

Figure 3-17 Occluded Front

Figure 3-17 depicts a profile of an occluded front. If either type of occlusion is arrived at from

the east, you would first encounter warm front type weather which may extend for several

hundred miles to the east of the surface front. On the other hand, if it were arrived at from the

west you would first encounter cold front type weather. The location of the occluded front is

significant to aircrews because the most severe weather, including ceilings and visibilities, is

generally located in an area 100 NM South to 300 NM North of the frontal intersection.

Figure 3-18 illustrates an overhead view of an occlusion.

Figure 3-18 Occluded Wave

311.

INACTIVE FRONTS

Clouds and precipitation do not accompany inactive fronts. Sometimes the warm air mass is too

dry for clouds to form even after the air is lifted and cooled. Inactive fronts may also be referred

to as dry fronts.

3-18 Mechanics of Frontal Systems