The Operational WRF NMM at NCEP

Two models within the Weather Research and Forecasting (WRF) system began running operationally at NCEP on 21 September 2004. The models are the 8 km NCEP Nonhydrostatic Mesoscale Model (NMM) and the 10 km NCAR Advanced Research WRF (ARW). Runs are made on domain "windows" within the NCEP NAM (Eta) domain and collectively cover the CONUS as well as Alaska, Hawaii, and Puerto Rico. The NMM has continued to change rapidly and its evolution will be described. These changes include modifications required to transition from Version 1.3 of the WRF framework to the current Version 2 and refinements of the model algorithms for improved forecast accuracy. Sample forecasts and statistics will be shown to illustrate the character and quality of the NMM's predictions. Plans for the WRF models in operations will also be summarized.