Towards the creation of the Global-2-Vortex Scale Hurricane Prediction System

Currently, the NWS relies on both coarse-scale global models and regional scale higher resolution models to provide numerical guidance for tropical cyclone (TC) forecasters. Primary models used for numerical guidance from NOAA are the GFS at 13-km equivalent grid spacing and the HWRF, which runs in a storm-centric mode with a single set of telescopic domains at 18-, 6-, and 2-km over each TC in the globe. Some significant progress was made with the regional HWRF system meeting the 5-year NOAA's Hurricane Forecast Improvement Project (HFIP) intensity goal. In general, the operational HWRF model has started showing its potential for improved intensity forecasts, producing comparable and sometimes superior results versus statistical models and NHC official forecasts; as demonstrated through a large set of retrospective forecasts. In the meantime, a new non-hydrostatic dynamic core was recently down selected to replace the GFS's spectral core.  The new dynamic core, Finite-Volume on Cubed-Sphere (FV3) was developed by NOAA/GFDL. Due to improved efficiency, it is expected to be operated at 7-10 km resolution by 2018. For seamless prediction of TC genesis, track, structure and intensity, "HWRF-type" of two way interactive nests may be embedded within the operational global model.

To investigate the technical and scientific challenges and merits of a multi-storm configuration, HFIP supported HRD/AOML, along with its partners at NCEP/EMC and the Developmental Testbed Center (DTC), to create a basin scale configuration of HWRF that operates with multiple moving nests. This configuration, which is now an option in the centralized HWRF code, was run for the 2016 hurricane season and also in retrospective mode for the 2011-2014 seasons. Results from the basin scale HWRF will be presented to show that an extension of the multi nested basin scale paradigm to global model could be considered for the NOAA's Next Generation Global Prediction System (NGGPS).