Chapter 14 — AIR MASSES AND FRONTS 



209.68 



Figure 14-21. — Effect of mountains on a warm front. 



as cold fronts, and warm type occlusions behave 

 as warm fronts. The occlusion process is 

 accelerated when an open wave approaches a 

 mountain range because the warm front is 

 retarded while the cold front continues its 

 normal movement until it reaches the mountain 

 range. 



EFFECT OF OCEAN CURRENTS. — Ocean 

 currents have a modifying effect on frontal 

 movement. To understand why ocean currents 



have such an effect, it is necessary to consider 

 the movement of the currents. 



In middle latitudes, ocean currents carry 

 warm water away from the Equator along the 

 eastern coasts of continents, and carry cold 

 water toward the Equator along the western 

 coasts of continents. The most active frontal 

 zones of the winter season are found where 

 cold continental air moves over warm water 

 off eastern coasts. This situation is noticeable 

 over the Atlantic Ocean off the east coast of 



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