... alternately (See Figures 12. 5 and 12. 6) It is generally associated with light variable winds, often thundery in summer and dull or foggy or misty in winter In Figure 12. 5 the wind circulation ... PRESSURE A wedge shaped extension of an anticyclone between two areas of low pressure (See Figures 12. 4 and 12. 6) The isobars assume their greatest curvature along the axis of the ridge It is generally ... (concave towards low pressure) along a line called the trough line within a depression (See Figure 12. 6) The wind circulation, anticlockwise in the northern hemisphere, is indicated by the arrows...