High-resolution WRF Forecasts of Mid-21st Century Urban Extreme Heat Events

With a projected global increase in surface temperatures over the next several decades, it is anticipated an increase in cooling systems energy demands will occur, which could present a strain on electricity generation and transmission infrastructure during extreme heat events, especially in urban areas. The planning of adequate power systems for specific municipalities requires an assessment of plausible temperature extremes in the coming decades. This study analyzes relatively high-resolution WRF simulations of near-surface temperatures in Austin, TX and Des Moines, IA during heat wave events as forecast mid-century. The WRF model is initialized using global climate model data of roughly 1º spatial resolution and multiple nested grids to achieve one-meter resolution. An urban canopy model (UCM) is used within WRF to incorporate heat effects of varying urban characteristics such as average building height and width, green-area fraction, road-area fraction, and population density. UCM parameters are optimally tuned for both cities based on the WRF simulation of recent historical heat wave events as validated against ASOS data. WRF temperature forecast sensitivities to certain UCM parameters are investigated.