We are currently assimilating Doppler velocity and reflectivity observations from the KOUN 10-cm research radar into the NSSL Collaborative Model for Multiscale Atmospheric Simulation (NCOMMAS). We employ ensembles with ~50 members and model grids with ~1-km horizontal grid spacing. The focus of the experiments is to determine how well the development and movement of the Oklahoma City storm can be predicted if the model is initialized with observations during only the first-echo stage of the convective cells. We use the EnKF to assimilate approximately 5 volumes of radar data over a period of 30 min into NCOMMAS. Then, we produce 60- min forecasts initialized with the results of the EnKF assimilation.
Preliminary results are so far encouraging both the growth of the Oklahoma City storm and the weakening of other nearby cells are predicted. At the conference, we will discuss how the assimilation and prediction results depend on a number of factors, including the model grid resolution, the method for populating the initial ensemble, the number of radar-data volumes that are assimilated, and the model microphysical parameterizations.