Fog!                                                           11/5

     1.  Why do cold fronts move faster than warm fronts?
              A cold front moves by lifting a low density, warm air mass off the surface and pushing it along aloft where there
                  is little friction.  A warm front moves by pushing a high density cold air mass along the surface.   The warm
                  front therefore has the more difficult "task" and moves slower as a consequence.

    2.  Can cyclones be characterized by temperature since they contain air of a range of relative temperatures.
              All cyclones involve multiple air masses spanning a significant range of temperatures, but there are major
                  differences in what might be termed the "core temperature," the temperature at some height at the central position
                  of the surface low.  There are no specific terms to characterize this core temperature, just adjectives.  Generally the
                  core temperature of a cyclone will be determined by the amplitude of the associated upper-level ridges and troughs.
                  If a high amplitude ridge and a deep trough are west of the cyclone it will tend to be much colder than a cyclone
                  with a low amplitude ridge and shallow trough to its west.  On the surface, extra cold cyclones are often preceded
                  by extra warm advection.

    3.  Can fronts begin as occluded, then separate? 
               Most occluded fronts begin as a cold front overtakes a warm front and merging begins to occur.  However occluded
                  fronts can form separately from other fronts.  We do not observe occluded fronts splitting to become separate cold
                  and warm fronts.  We generally see fronts occurring with associated cyclones, although in some cases the
                  associated cyclone center may be hundreds or even thousands of miles away.  It is common however to observe
                  cyclones without associated fronts.

    4.  What is the difference in the wind direction at the surface and aloft? 
               Rarely are wind directions aloft the same as they are at the surface.  Sometimes they differ substantially.  However
                  they are related since winds aloft cause the formation of cyclones and anticyclones and then steer these surface
                  systems in their subsequent motions.  Imagine yourself looking up into multiple cloud layers.  If you first face into the
                  direction the lower clouds are moving, then turn to the direction the upper clouds are moving, the direction of your
                  turn enables you to determine the nature of any upper-level advection which may be occurring.  If you turn to your
                  right (a "veering wind") warm advection is occurring; if you turn to your left (a "backing wind") cold advection is
                  occurring

    5.  What would cause a cold front and a warm front to collide?
               Head-on collisions do not occur.  Collisions do occur only because faster moving cold fronts overtake slower warm
                  fronts which are usually moving in almost the same direction.