High Resolution WRF Simulation and Climatological Analysis of Severe Weather Events during the North American Monsoon

During the North American monsoon in late summer, the Southwest U.S. is prone to severe weather hazards such as lightning, high winds, flash flooding, and dust storms. Previous studies have determined favorable atmospheric conditions for growth and organization of monsoon thunderstorms, including precipitable water, convective available potential energy (CAPE), gulf surges, and transient inverted troughs. A series of criterion based on the favorable atmospheric conditions have been developed to identify severe weather events from observations and dynamically downscaled historical reanalysis data (1950-2010). To analyze the identified severe event characteristics during the North American monsoon, high-resolution simulations are needed at a convective resolving scale using the Weather Research and Forecasting (WRF) model. Observed radar data, when available, is used to determine whether simulations reasonably represent organized convection. The aforementioned criterion is also applied to select future extreme weather events in dynamically downscaled CMIP3 and CMIP5 models. This research will ultimately lead to improved understanding of how monsoon severe weather will evolve in the future.