A Global to Local Scale Hurricane Forecast system

In order to forecast Tropical Cyclone structure, size and intensity changes with fidelity, the inner core structure of these storms must be resolved at 1-3 km horizontal grid spacing. At the same time TC system can also move up to thousands of kilometers during its life cycle and interact with the evolving synoptic-scale environment. Although the operational HWRF system is starting to show some exceptional skills in intensity forecasting and is being used over all basins in the globe for track and intensity guidance, the current HWRF configuration is storm centric and single nested, not ideal for representing multi-scale interactions or for post landfall applications, and is greatly limited in extending forecast lead times beyond 5 days. The primary goal of NOAA's next generation, High Impact Weather Prediction Project (HIWPP) is to accelerate the development of a global non-hydrostatic weather prediction system capable of running at ~3-km resolution in an operational forecast environment by late in this decade. Although global non-hydrostatic models are being envisioned to be run at higher resolutions by the end of this decade, it remains to be seen if these models can routinely operate at a uniform, 1-3 km resolution, providing reliable forecasts four times a day. Grid nesting appears to provide a reliable and practical approach for the hurricane-forecasting problem both at the regional as well as the global scale. Supported by HIWPP, the Hurricane Research Division (HRD) of the Atlantic Oceanographic and Meteorological Laboratory (AOML) with its partners at Environmental Modeling Center (EMC), National Centers for Environmental Predictions (NCEP) are creating the next generation multi-nested global to local scale hurricane forecast system (HFS). Residing within the NOAA Environmental Modeling System (NEMS) framework, this system will utilize the Non-Hydrostatic Multi-Scale Model (NMMB) dynamic core and utilize the HWRF physics and initialization, which have been the key to the success of the HWRF system. The system is envisioned to be run in both regional and global mode. We will demonstrate the feasibility of operating a multi-nested global model and illustrate the importance of multi-scale interactions for the hurricane problem.