RAPID: Preliminary Scientific and Sociological Assessment of the Southeastern U.S. Tornado Outbreak of 27 April 2011

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A widespread outbreak of exceptionally damaging severe thunderstorms, many of which bore unusually intense and long-track tornadoes, swept across the southeastern U.S. on 27 April 2011. The death toll for this regional disaster stands at well over 300, with a majority of these fatalities occurring across Alabama. The primary objectives of this study are (i) to provide timely assessment of those meteorological factors (synoptic to mesoscale) and external influences (e.g., atmospheric thermal boundaries and gravity-wave forcing, influences of local topography and surface roughness etc.) impacting tornadogenesis, modulation of tornado intensity, and resultant variations in damage and loss of life; (ii) to conduct a preliminary analysis of the variability in structure of storms producing significant tornadoes over a relatively compressed span of time; (iii) to further evaluate and quantify damage characteristics of select tornadoes at high spatial resolution via aerial and ground-based surveys; and (iv) to assess the public's response to issued tornado warnings and perceived tornado threat. Related goals are to better understand why fatality counts were so high, and to explore ways to mitigate loss of life in future severe weather events in this region. This latter effort will be coordinated with a recently completed NOAA/National Weather Service Assessment of this historic outbreak. Research quality dual-polarimetric and dual-Doppler radar analyses will be developed with attention to more timely and reliable identification of signatures linked to severe storm behavior using modernized observing technologies. A workshop bringing together a variety of research and operational meteorologists and emergency managers familiar with this historic outbreak will be conducted in Huntsville, and a related article will be prepared for submission to the Bulletin of the American Meteorological Society.The intellectual merit of this effort centers upon identification of those mechanisms responsible for sharp spatial and temporal variations in observed storm characteristics and the remarkable intensity of tornado damage that occurred on 27 April 2011, with particular attention to any aspects that may be unique to the atmospheric environment or underlying topography typical of the southeastern U.S. Broader impacts will accrue through development of a comprehensive dataset will provide new and supporting information on real-time diagnosis of radar signatures of tornadoes, student education, and via outreach to a variety of meteorological experts and first responders responsible for safeguarding the public.