Contribution of snowfall from diverse synoptic conditions in the Catskill/Delaware Watershed of New York State.

Snowfall in the six basins of the Catskill/Delaware Watershed in south-central New York State historically contributes roughly 20-30% of the water resources derived from the watershed for use in the New York City water supply. The watershed regularly experiences snowfall from three distinctive weather patterns: coastal mid-latitude cyclones, overrunning systems, and lake-effect or Great Lakes enhanced storms. Using synoptic weather classification techniques, these distinct regional atmospheric patterns impacting the watershed are isolated and analysed in conjunction with daily snowfall observations from 1960 to 2009 to allow the influence of each synoptic weather pattern on snowfall to be evaluated independently.