The HWRF modeling system had a major upgrade in 2012, where for the first time an operational hurricane model at NCEP was run at a cloud-resolving 3 km horizontal resolution, laying the foundation for significantly improved hurricane forecast skill. In this year's (2013) upgrades, the hurricane team at EMC took advantage of the better scaling of HWRF model on the new WCOSS Linux architecture and explored the full potential of the high resolution hurricane dynamics and physics. As a result, in addition to the great improvement of forecast skills noted in the 2012 HWRF (10-15% for intensity and 15-20% for tracks), the 2013 HWRF model was found to exceed the track forecast skill by more than 15% and, most importantly, exceeded the intensity forecast skills by about 10-15% compared to the 2012 HWRF model. Evaluation of retrospective forecasts for three hurricane seasons (2010-2012) indicated that the 2013 HWRF model exhibits better intensity forecast skill than NHC official forecasts for the Atlantic basin tropical cyclones (Figure 1). The HWRF model intensity errors are much smaller than the statistical model errors at all forecast periods. This remarkable intensity prediction skill from a deterministic dynamical model compared to official or statistical models is unprecedented. In addition to the improvements in intensity forecasts, the track forecasts (Figure 2) also showed significant improvements from the 2013 HWRF compared to the 2012 HWRF, and are comparable to those of the best performing NCEP's Global Forecast System (GFS).
Operationally, the HWRF model provides forecast guidance to the hurricane forecasters at the National Hurricane Center (NHC) and Central Pacific Hurricane Center (CPHC) for all tropical cyclones in the North Atlantic, North Eastern Pacific and North Central Pacific basins. In addition, with support from NOAA's Hurricane Forecast Improvement Project (HFIP), starting with the 2012 typhoon season, the hurricane team at NCEP's Environmental Modeling Center (EMC) has been providing experimental real-time guidance to the forecasters at US Navy's Joint Typhoon Warning Center (JTWC) for all tropical cyclones of the North Western Pacific basin. JTWC has decided to include the 2013 version HWRF model in their official consensus model, which is unprecedented for non-operational models in that basin. Other international weather agencies from different countries such as China, Taiwan, India, Vietnam and Oman have expressed interest in using the HWRF model for their operational tropical cyclone forecast needs. HWRF is operational at the India Meteorological Department (IMD) for tropical cyclone forecasts over the North Indian Ocean basin, making NOAA's HWRF model a unique and specialized tropical cyclone forecast model for all Northern Hemispheric ocean basins.
Future developments of the HWRF model are planned, including implementing more sophisticated physics packages applicable for high-resolution assimilation of satellite data in all sky conditions, and better utilization of flight level data from reconnaissance aircraft. Efforts will also continue to develop and upgrade the HWRF ensemble prediction system. Expanding the ocean model to other basins and coupling the HWRF model to land, wave, surge and hydrology models are other developmental paths EMC has chosen leading to the next generation comprehensive hurricane forecast modeling system.