NGGPS FV3GFS Development for Q2FY19 Operational Implementation

NOAA selected the GFDL finite­ volume cubed-sphere dynamical core (FV3) as the Next Generation Global Prediction System (NGGPS) dynamical core. NCEP has implemented the dycore into the NOAA environmental modeling system infrastructure, updated its global data assimilation system to exchange information between the forecast model on cubic-sphere grids and data assimilation on Gaussian lat-lon grids, and developed a new workflow system for both research and operation. FV3GFS is scheduled to be implemented into operation in Q2FY19 to replace the global spectral model, which has been used in operation by NOAA in the past 38 years. This FV3GFS version uses the same physics package as the current operational GFS except for 1) the replacement of Zhao-Carr microphysics with the more advanced GFDL microphysics, 2) an updated parameterization of ozone photochemistry with additional production and loss terms, 3) a newly introduced parameterization of middle atmospheric water vapor photochemistry and, 4) a revised bare soil evaporation scheme. We present here the development process of an end-to-end fully cycled FV3GFS-based NWP forecast system with data assimilation, the setup of retrospective and real-time experiments, and an assessment of the model perform in terms of large-scale statistics of a few key parameters against the current operational model.