An important limitation of numerical hurricane track forecasts is the difficulty in coaxing the vortex to assume the correct initial motion. Results from a semispectral, barotropic, linear model suggest a remedy. When the model is initialized from axisymmetry and rest in a quiescent environment on a Northern Hemisphere β plane, the vortex moves toward the northwest. The asymmetric streamfunction field is a dipole such that flow between the cyclonic and anticyclonic gyres advects the vortex. This asymmetry appears to reflect a free oscillation because the asymmetric structure, and the induced motion, persists for a long time in the absence of forcing. Experimentation with a variety of axisymmetric vortex structures suggests that, existence of the previously described modes is a general property of barotropic vortices scaled to resemble hurricanes. -from Author
