When the word Storms is used in relation to climatic
   controls, we are not talking about tornadoes, hurricanes and the
   like. Rather this control deals with the presence of moisture in
   the atmosphere, the various means by which moisture is removed
   from the atmosphere and the forms the moisture takes.
   Meteorologists are very interested in the amount of moisture in
   the air not only because the presence of water vapor is an
   indicator of the potential for precipitation, but the energy
   released as water vapor changes states provides the energy for
   storms.
   
   
   
    Moisture, or humidity, is a general term we will use to
   describe the amount of water vapor in the air. There are a number
   of ways to express the amount of humidity in the air -- the most
   common being absolute humidity, relative humidity and mixing
   ratio. We will take up each of these shortly.