“Tale of Three Blizzards”

  Introduction: The winter of 2009-2010 was unique in the Washington, DC, area. Three strong frontal cyclones achieved blizzard status in the Mid-Atlantic region. The first, on 19 December 2009, paralyzed Montgomery County with almost 30 inches of snow in some areas. The second and third storms hit the county during a single week in February, each dumping more than 20 inches of snow. While the results of all three cyclones were similar, the storms themselves were remarkably different. In each case the active weather was triggered by different sets of wind and moisture patterns at the surface and in the upper troposphere. Compare and contrast the three events by selecting and rank-ordering the triggers that had the greatest influence in each storm.