Significant Advances to the NCEP Operational HWRF Modeling System for Improved Hurricane Forecasts

Significant advancements to the National Centers for Environmental Prediction (NCEP) operational atmosphere-ocean coupled Hurricane Weather Research and Forecast (HWRF) modeling system implemented for 2013 hurricane season has resulted in providing more skillful track and intensity forecast guidance in the North Atlantic (ATL) and North Eastern Pacific (EPAC) basins to the forecasters at the National Hurricane Center (NHC). Apart from improved track and structure forecasts, for the first time, the high-resolution HWRF model operating at cloud-permitting 3km resolution has shown superior intensity forecasts compared to the best performing statistical models and the NHC official forecasts.

With support from NOAA's Hurricane Forecast Improvement Project (HFIP), HWRF is also providing experimental real-time guidance for tropical cyclones in the Central North Pacific (CPAC), Western North Pacific (WPAC) and North Indian Ocean (NIO) basins in support of operational use by the forecasters at the Joint Typhoon Warning Center (JTWC). Superior track and intensity forecasts from operational HWRF led the model being recognized as the best performing operational tropical cyclone model in all Northern Hemispheric oceanic basins. Focused research and developmental efforts, systematic testing and evaluation, efficient mechanism for Research to Operations (R2O) through dedicated code management and support are key elements for this accomplishment supported by HFIP.

Major upgrades implemented for the 2013 HWRF model include, for the first time, assimilation of real-time NOAA P3 aircraft Tail Doppler Radar (TDR) data using sophisticated regional hybrid assimilation technique, apart from several enhancements to the model dynamics, physics and vortex initialization. Advanced nest movement algorithm and improved nest-parent interpolations have also resulted in more efficient storm tracking in the model forecasts.

This presentation will focus on describing the end of the season performance of 2013 operational HWRF for Atlantic, Eastern Pacific, Western Pacific, and North Indian Ocean basins. Efforts for further advancements to the HWRF modelling system for improved tropical cyclone prediction capabilities for 2014 hurricane season will be presented. Ongoing developments include emphasis on a basin-scale domain with multiple moveable nests to track multiple storms, advanced hybrid EnKF-VAR data assimilation with improved use of satellite radiances in all weather conditions and all available inner core aircraft reconnaissance data, improved physics to address rapid intensity changes and relevant structure changes. Additional products from operational HWRF will include applications for landfall related storm surge, rainfall, inundation and tornadic potential.

Further improvements in tropical cyclone track, intensity and structure prediction skills will continue to be the major focus areas with special emphasis on predicting the rapid intensity changes. These efforts are carried out in collaboration with several NOAA and academic partners, and this presentation will also highlight the efficient mechanism established for research transitioning to operations.