- At a cold front, a cold air mass takes the place of a warm air mass and forces the warm
air upwards. - The opposite occurs at a warm front, except that the warm air slips above the cold air
mass. - In an occluded front, a warm front is overtaken by a cold front, which creates variable
weather.
Review Questions
- What type of air mass will be created if a batch of air sits over the equatorial Pacific
Ocean for a few days? What is the symbol for this type of air mass? - What conditions must be present for air to sit over a location long enough to acquire
the characteristics of the land or water beneath it? - Discuss how latitude affects the creation of air masses in the tropical, temperate and
polar zones. - Phoenix, Arizona is a city in the Southwestern desert. Summers are extremely hot.
Winter days are often fairly warm but winter nights can be quite chilly. In December,
inversions are quite common. How does an inversion form under these conditions and
what are the consequences of an inversion to this sprawling, car-dependent city? - Why are the directions fronts move in the Southern Hemisphere a mirror image of the
directions they move in the Northern Hemisphere? - How is a stationary front different from a cold or warm front?
- What sorts of weather will you experience as a cold front passes over you?
- What sorts of weather will you experience as a warm front passes over you?
- How does an occlusion form?
- What situation creates a cold occlusion and what creates a warm occlusion?
Further Reading / Supplemental Links
- Cold Front animation, Goddard Space Flight Center http://svs.gsfc.nasa.gov/
vis/a000000/a002200/a002203/index.html
Vocabulary
air mass A large mass of air with the same temperature and humidity characteristics,
although these characteristics may change with altitude.
cold front A front in which a cold air mass is replacing a warm air mass; the cold air mass
pushes the warm air mass upward.
front The meeting place of two air masses with different characteristics.