Dry air entrainment into a mid-latitude winter storm can have a variety of effects on subsequent snowfall, including the creation of banded heavy snowfall and influences on when the snow begins, its northern extent, and ultimately storm-total snowfall. The objectives of this study are to examine a single storm in detail and then perform comparison studies to determine: 1) where dry air originates in selected extratropical cyclones (ETC); 2) the dimensions of the dry and cold conveyer belts in each ETC; 3) how the dry and cold conveyor belts become incorporated into each ETC; and 4) the influence of the dry and cold conveyor belts on ETC morphology and associated precipitation structures.