Severe Convective Windstorms

Severe convective windstorms are high-impact events that can cause widespread swaths of damage and generally occur across the eastern two-thirds of the United States. This presentation will begin with a brief review of different types of severe convective windstorms including: bow echoes, mesovortices, derechos, high-precipitation supercells, and heat-bursts. Current understanding of the key dynamics and climatology of these different types of severe convective windstorms will be summarized. This presentation will then focus on mesoscale convective systems and associated smaller-scale mesovortices. A case study of a multi-scale numerical simulation of the 8-9 May 2007 Oklahoma MCS and line-end vortex will be examined to illustrate the short-term predictive aspects of MCSs and associated mesovortices. The importance of near-storm low-level shear for the numerical prediction of such systems will be emphasized. This same numerical simulation will then be discussed in the context of the dynamics of a long-lived mesovortex that spawned several tornado-like vortices. The development of a horizontal rotor that played a key role in tornadogenesis in this case will also be examined. This talk will conclude with a look at future challenges and outstanding questions pertaining to severe convective windstorms. Emphasis will be given to those challenges and issues related to MCSs and mesovortices.