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HMON which stands for Hurricanes in a Multi-scale Ocean-coupled Non-hydrostatic model is a new Hurricane forecast system running operationally at NCEP. This version, HMON v1.0.0, is the first version for the system. This release has been fully tested and compared with the discontinued Geophysical Fluid Dynamics Laboratory (GFDL) Hurricane Model (GHM) results and is considered its replacement. It has shown significant skill improvements in terms of storm track and intensity forecasts in Northern Atlantic (NATL), Eastern Pacific (EPAC) and the Central Pacific (CPAC) basins. HMON also provides a first step for the NCEP Environmental Modeling Centers' (EMC) efforts towards unification of operational models within the NOAA Environmental Modeling System (NEMS) framework.

The dynamical core of HMON is the Non-hydrostatic Multi-scale Model on a B grid (NMMB). It has 43 vertical levels with the model top fixed at 50 hPa. It includes vortex relocation, but has no data assimilation. It has been coupled to the HYCOM ocean model for EPAC and CPAC basins but runs uncoupled for the NATL basin. The HMON model runs on-demand with input provided by the National Hurricane Center (NHC) and consists of multiple movable two-way interactive nested grids that follow the projected path of a tropical system.