Updates to the Global Wave Forecast System at NCEP: Impacts of Surface Ocean Currents, Objective Physics Optimization, High-Resolution Spatial Grids, and Coupling to the Global Forecast System

The US National Centers for Environmental Prediction (NCEP) runs a global deterministic wave forecast system (wave_multi_1), providing operational wave guidance to the US National Weather Service. The wave_multi_1 system consists of an implementation of the WAVEWATCH III model framework using a mosaic of two-way nested grids, and runs 4 daily cycles with forecasts extending to 7 days. Upgrades to the wave_multi_1 system for FY19 will include several features in preparation to a paradigm whereby NWP models will become coupled via the NOAA Environmental Modeling System (NEMS). New features will include coupling of wave fields to ocean surface currents, retuning of wave model physics using a state-of-the-art optimization approach, and a new high-resolution system of two-way nested grids. Details of these features, and their impacts to the skill of NCEP’s operational wave guidance are presented and discussed. A description of the new coupled NEMS paradigm from the perspective of its wave model component is also presented, as well as a preliminary discussion of its impacts to products and wave model skill.