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Name_____________________________ Date_________________________ Section___
WEATHER FRONTS
Within a natural or designed system, the transfer of energy drives
the motion and/or cycling of matter. Therefore, the movement of
water and energy in the atmosphere can determine weather
patterns. For example, many weather patterns are caused by
differences of temperature in air masses.
Fronts occur at the boundary where warm and cold air masses meet. There are four types of
fronts: cold front, warm front, stationary front, and occluded front. Warm air masses are
forced to rise and expand over and above cold air masses, and cold air masses wedge
underneath warmer air masses. Cool air is more dense and tends to sink. Warm air is less dense
and tends to rise. As the warm air cools, the moisture condenses to form clouds. Rain or snow
may form if the warm air continues to rise and expand.
Cold Front: A cold front is a situation where a cold air mass is advancing upon a
warm air mass. Cold, dense, high pressure air mass moves quickly towards a warm, less
dense, low pressure air mass. The warm air rises quickly producing fast, violent
thunderstorms followed by clear skies.
Cold fronts produce cumulonimbus clouds (anvil shaped, thunderstorm clouds). Big thunderstorms in
the summer and snowfalls in the winter are the weather conditions associated with cold fronts.
