Testing and Evaluation of the Radar Data Assimilation and Its Impact on Convective Forecast for the 3-Km High Resolution Regional Applications

As one of the main organizations facilitating the transitions between the research and operations, the Developmental Testbed Center (DTC) continues to serve as a bridge between the research and operational data assimilation communities and conduct testing and evaluation of the GSI (Gridpoint Statistical Interpolation) hybrid Ensemble-Variational system for regional 3-km High Resolution Rapid Refresh (HRRR), as part of the efforts to improve the convective scale and cloud resolving numerical weather predictions at the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL). Due to computational constraint, the operational 3-km HRRR domain has been reduced from the CONUS (Continental US) to the central US. The period for the testing and evaluation is set to be September 3-10 of 2016, with hourly update of the initial and boundary conditions from the retrospective 13-km Rapid Refresh (RAP) runs. The primary candidate for this testing and evaluation activity is radar data assimilation. After a functionally similar operational HRRR system has been set up on the NCAR supercomputers, a number of experiments are conducted using various configurations of radar data assimilation within the GSI. The forecast impact has been examined, as compared to the experiment with default configuration of the HRRR framework.