Description and Evaluation of NORAPS: The Navy Operational Regional Atmospheric Prediction System

A complete regional forecast system (NORAPS) has been developed for the Navy. The forecast grid is globally relocatable and can be set to any size and resolution. NORAPS performs wind and mass analyses, a static initialization, and computes a terrain field for whatever grid is chosen. The forecast model includes an efficient time integration scheme, cumulus parameterization, large-scale precipitation, latent and sensible heat fluxes over water, and one-way interactive boundaries. NORAPS was tested on 30 forecasts over the Mediterranean region. Average objective scores for these forecasts indicated that NORAPS represented an improvement over the current Fleet Numerical Oceanography Center's hemispheric model. One case of strong cyclogenesis was rerun with 10 levels instead of the five used in the original run. Improvements were noted in the forecast intensity and intensification rate.