In this research it is established a classification system by which to characterize atmospheric conditions, specifically those related to winter extra tropical storms and fair weather. Numerous classification schemes have been proposed to categorize atmospheric conditions in a variety of environments-however, since meteorological processes are inherently complicated, these are of necessity based on criteria that suit a particular purpose. The system employed in this project was ultimately designed to differentiate between: 1. fair weather and storm conditions;2. different phases of extratropical storms;3. extratropical storms of different intensities and synoptic types.