A description of the real-time HFIP Corrected Consensus Approach (HCCA) for tropical cyclone track and intensity guidance

This study discusses the development of the Hurricane Forecast Improvement Program (HFIP) Corrected ConsensusApproach (HCCA) for tropical cyclone track and intensity forecasts. TheHCCAtechnique relies on the forecasts of separate input models for both track and intensity and assigns unequal weighting coefficients based on a set of training forecasts. TheHCCAtrack and intensity forecasts for 2015were competitivewith some of the best-performing operational guidance at the National Hurricane Center (NHC); HCCA was the most skillfulmodel forAtlantic track forecasts through 48 h.Average track inputmodel coefficients for the 2015 forecasts in both the Atlantic and eastern North Pacific basinswere largest for theEuropeanCentre forMedium- Range Weather Forecasts (ECMWF) deterministic model and the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) ensemble mean, but the relative magnitudes of the intensity coefficients were more varied. Input model sensitivity experiments conducted using retrospective HCCA forecasts from2011 to 2015 indicate that the ECMWFdeterministicmodel had the largest positive impact on the skill of theHCCAtrack forecasts in both basins. Themost important inputmodels forHCCAintensity forecasts are the Hurricane Weather Research and Forecasting (HWRF) Model and the Coupled Ocean-Atmosphere Mesoscale Prediction System-Tropical Cyclone (COAMPS-TC) model initialized from the GFS. Several updates were incorporated into the HCCA formulation prior to the 2016 season. Verification results indicate HCCA continued to be a skillful model, especially for short-range (12-48 h) track forecasts in both basins.