Development and Evaluation of NEMS GFS for 2017 Implementation

A common modeling framework called the NOAA Environmental Modeling System (NEMS) has been in development in recent years to facilitate the development and transition to operation of NCEP numerical models.  NEMS is a shared, portable, high performance software superstructure and infrastructure.  It has been identified as the exclusive modeling environment of NOAA’s Next Generation Global Prediction System (NGGPS).  In the past year, major effort has been invested in speeding up the conversion of the NCEP Global Forecast Systems (GFS) to the NEMS environment.  The NEMS GFS is currently under intensive testing and evaluation, and is scheduled to be implemented for operation in the third quarter of 2017.  Along with this implementation, both the model physics and data assimilation system will also be upgraded.  In particular, the deep and shallow cumulus convection schemes will be updated to use scale- and aerosol-aware parameterizations.   The land surface model will adopt new and more advanced land datasets including new soil and vegetation types, MODIS snow-free albedo and maximum snow albedo.  A prognostic model for near sea-surface temperature will be included in both the forecast model and the data assimilation system.  In this presentation we will describe the upgrades of NEMS GFS physics, data assimilation and post processing for 2017 implementation, and evaluate the performance and forecast skills of retrospective and real-time experiments.