NCEP has implemented the first version of the Finite Volume Cubed Sphere (FV3) dynamical core based Global Forecast System (GFS v15) into operations in June 2019, replacing the spectral model based GFS. This is the first instantiation of NOAA’s Unified Forecast System (UFS) for Medium Range Weather Application in operations. The next major upgrade is for the Global Ensemble Forecast System (GEFSv12) which will use the same FV3 based global model with advanced stochastic physics perturbations, and 2-tiered SSTs, and for the first time, will be extending ensemble based weather predictions for sub-seasonal scales to 35 days. GEFSv12 comes with 20-year reanalysis and 31-year reforecasts to support stakeholder needs for calibration and validation, and 2.5 year retrospective forecasts provide basis for the scientific evaluation of GEFSv12. GEFSv12 will also unify the wave ensembles and aerosol capabilities with this implementation in support of simplifying the NCEP Production Suite. Development of GEFSv12 was a multi-year project involving collaborations with various community partners and stakeholders. This webinar describes the science changes for GEFSv12 and comprehensive evaluation of the ensemble performance for medium and extended range (weeks 3&4) weather predictions along with results from the evaluation of GEFS-Wave ensemble and GEFS-Aerosol components.
