WRF ARW modeling for T-REX at the U.S. Army Research Laboratory

The Advanced Research Weather Research and Forecasting (WRF-ARW) modeling system is being studied at the ARL as a potential short range predictive component of an Army tactical analysis/nowcasting system. This system is also called at ARL the Weather Running Estimate-Nowcast (WRE-N), and it is being tailored for tactical applications. The ARL is currently studying the WRF-ARW to see how well it simulates complex mountain and boundary layer meteorology at horizontal grid spacings down to 1-2 km. The 2006 Terrain-induced Rotor Experiment (T-REX) across the Owens Valley of California has provided an opportunity for ARL to run the WRF-ARW in both near real-time and research modes, and at fine-scale horizontal grid spacings. A large number of multi-agency (including international) groups collected surface, upper-air, remotely sensed, and aircraft observations during the March/April T-REX period. Thus, ARL is offered an ideal opportunity to test WRF-ARW under extreme topographical conditions, and to collaborate with other expert numerical weather prediction modeling groups running the same and other mesoscale models (including WRF-NMM and COAMPS) at similar fine scales. The main purpose of such collaborations would be to better understand model performance, strengths and weaknesses, parameterizations and formulations, etc. This paper summarizes the current/planned ARL modeling activities associated with T-REX, and provides some preliminary observations of the model's performance to date.