Factors Important for Tropical Cyclone Tracking in NWP Output

This paper will describe the algorithm used in the GFDL vortex tracker and also discuss factors that are critical in operational tracking of tropical cyclones in NWP output. The GFDL vortex tracker has been operational at NCEP since 1998 and provides objective tropical cyclone track, intensity and wind radii guidance based on NWP output. The location fixes diagnosed by the tracker are produced by averaging fixes from nine individual parameters, ranging in height from the surface up to 700 mb. This paper provides an analysis of which parameters are most important for inclusion in order to provide the most accurate position fixes as guidance and also to ensure that a storm can continue to be tracked and a reliable position fix can continue to be made through the time of lysis of a model storm.