Meteorological Overview and Initial Scientific Assessment of the Devastating 27 April 2011 Tornado Outbreak (Invited Presentation)

By many metrics, the tornado outbreak on 27 April 2011 was the most significant tornado outbreak since 1950, exceeding the super outbreak of 3-4 April 1974. The number of tornadoes over a 24 h period (midnight to midnight) was 199, the tornado fatalities and injuries were 316 and more than 2,400, respectively, and the insurable loss exceeded four billion dollars. In this paper, we provide a meteorological overview of this outbreak, and illustrate some unique features of three mesoscale events: a large early morning QLCS, a midday QLCS, and numerous afternoon supercell storms, using NWS and research radars, profilers, surface measurements, and images of the tornadoes. The primary motivation for this preliminary research is to present an initial scientific assessment of this outbreak, including documenting the diverse characteristics (i.e., mesoscale organization of deep convection) of this outbreak, examine preliminary analyses, summarize initial investigations of societal aspects, and discuss the future of severe weather and tornado research.