Future Climate Projections for Louisiana and Mississippi Using WRF: Are Extreme Heat and Precipitation Events Intensifying?

Abstract General circulation models (GCMs) lack the spatial resolution to capture the atmospheric and land-surface processes that shape regional climate. Regional climate models (RCMs) better resolve the interactions between large-scale weather patterns and local terrain. This study uses the Weather Research and Forecasting (WRF) model to perform high-resolution (12-km) dynamical downscaling for Louisiana and Mississippi over a historical (1996–2005) and a future (2090–2099) time span, forced by NCAR’s Community Earth System Model, version 1 (CESM1). Model performance was evaluated for the 1996–2005 period against atmospheric reanalysis and station observations, showing better skill for temperature than precipitation. Seasonal evaluation (winter: Dec-Feb; spring: Mar-May; summer: Jun-Aug; fall: Sep-Nov) indicates best performance in spring and fall, with r ≥ 0.93 and RMSE ≤ 0.72 °C for temperature, and r ≥ 0.88 and RMSE ≤ 56 mm for precipitation. Lower skill in simulating summer precipitation suggests caution when interpreting future projections. Future simulations (2090–2099) project notable widespread warming across all seasons. Precipitation changes are spatially variable and mostly insignificant, except for a significant Sep-Nov increase near the Gulf coast. Projected changes in extreme temperature indices suggest more frequent hot days along the Gulf coast and longer heatwaves in northern Louisiana and central–northern Mississippi. Contrasting trends of extreme precipitation frequency and intensity indices imply fewer but more intense precipitation events in northern Louisiana by the late 21st century. Insights from this work will contribute toward a comprehensive understanding of the potential impacts of climate change on the Gulf coast. Graphical Abstract This graphical abstract provides a concise visual summary of a regional climate modeling study that uses the Weather Research and Forecasting (WRF) model to dynamically downscale outputs from a General Circulation Model for Louisiana and Mississippi. The WRF model, validated against gridded and station data from 1996 to 2005, shows better performance for temperature than for precipitation, especially in spring and fall. Future simulations project widespread warming across all seasons, while precipitation changes are more spatially variable, with a notable increase in the fall likely due to intensifying tropical cyclones. However, the model performs poorly in summer for precipitation, urging caution when interpreting seasonal projections. The study also highlights that extreme precipitation events are expected to become fewer but more intense, and that extreme temperature days will become more frequent along the Gulf Coast with longer heatwaves inland. Overall, the research supports regional planning efforts by offering fine scale climate projections that are essential for understanding future climate impacts in the Gulf Coast region.