Normal mode initialization of the nested grid model of the Meteorological Center

"Work is underway at the National Meteorological Center to improve the numerical analysis and forecast system in preparation for the scheduled upgrade of computational capability this year. Under the new system, very high priority will be given to improving operational forecasting of major precipitation events. One of several numerical models under consideration to supplement the Limited-area Fine-mesh Model (LFM) in this effort is the NMC Nested Grid Model (NGM). In this paper we will describe our efforts to overcome a key hurdle in implementing a regional-scale forecast model such as the NGM--initialization. The application of normal mode initialization to regional-scale models has been studied recently at NMC. Investigation has followed two paths. One approach involves determining the normal modes of the regional-scale model itself. In the second, normal mode initialization of a global or hemispheric model provides the initial conditions for the regional scale model. Discussion of the latter approach will be presented here. Our experimental procedure, including description of the analysis and initialization steps, is provided in the next section. Section 3 details the results of the experiments, with concluding remarks in Section 4"--Introduction. James E. Hoke, Norman A. Phillips, and Joseph G. Sela. "April 1983." "This is an unreviewed manuscript, primarily intended for informal exchange of information among NMC staff members." System requirements: Adobe Acrobat Reader. Includes bibliographical references. 1983 NWS (National Weather Service) NCEP (National Centers for Environmental Prediction) Library Public Domain 2285