 Cold fronts and occluded fronts generally move from west to east , while warm fronts move poleward . Because of the greater density of air in their wake , cold fronts and cold occlusions move faster than warm fronts and warm occlusions . Mountains and warm bodies of water can slow the movement of fronts . When a front becomes stationary , and the density contrast across the frontal boundary vanishes , the front can degenerate into a line which separates regions of differing wind velocity , known as a shearline . This is most common over the open ocean . 
