Monday, 12 January 2004
Simulation of the 27 May 1997 central Texas tornadic storms: Cell development and the role of the preexisting boundary
The aim of this work is to identify the specific role played by a preexisting boundary on cell development and storm maintenance in an environment similar to the air mass that characterized the 27 May 1997 severe convection over central Texas. A supplementary objective of this work is to examine the implication of storm-boundary interactions in high-CAPE, low-shear environments on short term forecasting. In the earliest observational study of this case, Magsig concluded that the preexisting boundary did not play a direct role in tornadogenesis. The radar analysis of Houston and Wilhelmson found that the preexisting boundary did seem to play a direct role in cell development and storm maintenance however, the precise causal relationship between the preexisting boundary and cell development has yet to be identified. Furthermore, the implication of such a relationship for the short-term forecasting of severe convection in similar high-CAPE, low-shear environments remains unresolved. The plan for this work is to undertake simulations of deep convection in an environment representative of this event using the Illinois Collaborative Model for Multiscale Atmospheric Simulations. Primary experiments aim to determine if the interaction between the preexisting boundary and storm generated gust fronts alone is sufficient to initiate cell development and promote storm maintenance. Additional experiments will explore the possible role that multiple preexisting boundaries may have played in cell development.