Fig. 1. Plots of the final points on the trajectory of a shallow-water, barotropic, hurricane-like vortex moving for 240 h on a beta plane (a) in a quiescent environment, (b) in a uniform 5 m/s westerly current, and (c) in a uniform 5 m/s easterly current. Clearly, the total motion converges to within 5 km for circular domains > 4000 km in radius. The system exhibits similar behavior for sheared zonal flows.