1. HWRF is an ocean-coupled NCEP regional operational typhoon forecast model, with 18-, 6-, and 2-km moving nested domains to better capture the detailed processes of air-sea interactions. The uncoupled runs, UH with HYCOM higher-resolution SST and UG with GFS SST cannot capture the southward deflection of Megi (2016) near landfall compared to the coupled runs CH with HYCOM SST or CG with GFS SST, indicating the great impact of air-sea coupling on the track prediction of typhoons approaching Taiwan.