When the air upraises rapidly and takes with it an abundant amount of moisture, then a storm forms. The storms called frontal storms, are just one way in which air is pulled up into the atmosphere.

A front is a boundary between warm air (to the South), and cold air (to the North). There are also tropical storms, which have very low pressure and wind rotation, and they usually develop in the tropics. Actually a tropical storm is classified in the same way as a hurricane. The wind speed is a determining factor; wind speeds within a tropical storm must be between 39 and 73 miles per hour (or 63 to 118 kilometers per hour).