On the spatial variability of storm accumulations in Southeast Texas

This study quantifies the spatial variability of rain accumulations for a variety of storm types (i.e., systems associated with warm fronts, cold fronts, weak forcing, and upper level disturbances) in Southeast Texas. Rainfall statistics from more than 11 months of daily reports obtained from a special high-resolution gauge network in Brazos County are presented and categorized by large-scale forcing to determine the degree of spatial variability between each storm type. In addition, comparisons are made against the official National Weather Service observation at Easterwood airport to evaluate how representative the single point is of the average countywide precipitation. A convective/stratiform separation algorithm is used on multiple years of data collected by the Aggie Doppler Radar (ADRAD) in order to calculate average convective rainfall percent and areal coverage for each of the forcing types to help explain the degree of variability in gauge observations. Finally, storm total rainfalls derived from local radar are presented for select cases and compared with rainfall estimations by simulations using the Weather Research and Forecasting (WRF) model to determine how well the observed spatial variability is captured by a mesoscale model.