Electrical behavior of downburst-producing convective storms over the High Plains

A great body of research literature pertaining to microburst generation in convective storms has focused on thermodynamic factors of the pre-convective environment as well as storm morphology as observed by radar imagery. Derived products based on Geostationary Operational Environmental Satellite (GOES) sounder data have been found to be especially useful in the study of thermodynamic environments. However, addressed much less frequently is the relationship between convective storm electrification, lightning phenomenology and downburst generation. Previous research in lightning production by convective storms has identified that electrification, phenomenology (i.e. flash rate, density), and polarity are dependent upon the thermodynamic structure of the ambient atmosphere, especially vertical moisture stratification. Thus, relevant parameters to describe the thermodynamic setting would include convective available potential energy (CAPE), due to its influence on updraft strength, and moisture characteristics of the boundary layer, due to its relationship to precipitation physical processes. It has already been addressed that buoyant energy and moisture stratification are important factors in convective storm development and downburst generation. This research effort investigates and derives a qualitative relationship between lightning phenomenology in convective storms and downburst generation. Downburst-producing convective storms will be analyzed by comparing pre-convective environments, as portrayed by GOES microburst products, storm morphology, as portrayed by radar imagery, and electrical behavior, as indicated by National Lightning Detection Network (NLDN) data. In addition, this paper will provide an update to validation efforts for the GOES Wet Microburst Severity Index (WMSI) and Hybrid Microburst Index (HMI) products to include data from both the 2005 and 2006 convective seasons. The case study presented will demonstrate the effectiveness of the coordinated use of the GOES WMSI and HMI products during convective storm events over the southern High Plains.