Depressions Depressions Depressions, sometimes called mid-latitude cyclones, are areas of low pressure located between 30 and 60 latitude.
Depressions develop when warm air from the sub-tropics meets cold air from the polar regions.
Depressions usually have well defined warm and cold fronts, as the warm air is forced to rise above the cold air. The warm and cold fronts associated with depressions bring with them characteristically unsettled weather. A depression develops like the propagation of a wave in water. In the immediately surrounding area the pressure begins to fall. A disturbance of this kind is called a wave depression.