<P> Occluded fronts are indicated on a weather map by a purple line with alternating half - circles and triangles pointing in direction of travel . The trowal is indicated by a series of blue and red junction lines . </P> <P> A stationary front is a non-moving (or stalled) boundary between two air masses, neither of which is strong enough to replace the other . They tend to remain essentially in the same area for extended periods of time, usually moving in waves . There is normally a broad temperature gradient behind the boundary with more widely spaced isotherm packing . </P> <P> A wide variety of weather can be found along a stationary front, but usually clouds and prolonged precipitation are found there . Stationary fronts either dissipate after several days or devolve into shear lines, but they can transform into a cold or warm front if conditions aloft change . Stationary fronts are marked on weather maps with alternating red half - circles and blue spikes pointing in opposite directions, indicating no significant movement . </P> <P> When stationary fronts become smaller in scale, degenerating to a narrow zone where wind direction changes significantly over a relatively short distance, they become known as shearlines . A shearline is depicted as a line of red dots and dashes . Stationary fronts may bring snow or rain for a long period of time . </P>

What type of front would cause several days of rain and clouds