Extending Operational HWRF Initialization to Triple-nest HWRF System

The operational HWRF initialization has been extended to 3km triple-nest HWRF system. The initialization can be considered as a mini-analysis for background vortex+GSI. The mini vortex analysis makes small corrections to model-systematic errors of the storm position, storm size and storm intensity forecasts. The vortex analysis consists three parts: 1) storm relocation, 2) storm size correction, 3) storm intensity correction. The vortex analysis can be combined with other data analysis systems such as 3D-VAR, EnKF and hybrid systems and produce better results. In triple nest initialization, we upgraded the interpolation subroutines which has large errors in both 3km and 9km interpolation, we also generalized the intensity calculation for 10m wind. Preliminary tests show that significant improvements in both track and intensity forecasts can be achieved using the HWRF triple-nest system.