Multi-Scale Dynamics Resulting in the February 11-12, 2010 South Central U.S. Snowstorm

This study investigates the synoptic and mesoscale dynamics responsible for the February 11-12, 2010 record breaking snowfall event across the south central U.S. An analysis of this event is presented to show the contributing factors that played an important role using observations and numerical simulation results from the Weather Research and Forecasting model. This record snowfall event represents an example of decelerating multiple (polar and subtropical) jet streaks and their accompanying mesoscale baroclinic zones which are extremely difficult to accurately forecast. These jets are restructured in part by synergistic interactions with upscale diabatic forcing initiated by low-level flow blocking in the complex terrain of West Texas. The interactions among the jets and terrain generate zonally-oriented meso-beta scale snow bands that represent upright and slantwise convective forcing. Three key findings in this research are that: 1) multiple frontal interactions create a favorable environment for upscale development of precipitation events when properly juxtaposed with the blocking of complex terrain, 2) the complex terrain of western Texas can become important to downstream heavy snowfall over the south central U.S. when multiple jet/front systems and diabatic heating are triggered by deep mesoscale adjustments and 3) the heavy snowfall event is only indirectly related to low-level coastal cyclogenesis which is not critical to the record snowfall event.