A Mesoscale NWP Study of a Convective Outbreak over South Australia

Abstract

 On two successive days in November 1979, lines of convection developed over South Australia, with widespread damage occurring on the second day. In this paper the quality of the numerical weather prediction guidance for these two events is assessed, using a mesoscale (75 km grid spacing) NWP model. It is shown that model forecasts of divergence, low level flux convergence of moist static energy (FCE), stability indices, and vertical motion provide high quality forecast guidance. It is shown that the position of the low level moist tongue, and maxima in the fields of moist convective instability and low level convergence were common to both events. However the greater magnitude of these indicators, a greater 1000-500 mb shear, and a stronger frontogenetic forcing near the convective line the second day do suggest the potential for more intense convection on that afternoon.