Three vortices in a polar air stream are analyzed using detailed mesoscale observations and conventional synoptic data. In their mature stages, the vortices exhibited wind, temperature and precipitation patterns similar to the larger extratropical cyclones that form on the polar front. Each of the three vortices interacted with the polar front to form an “instant occlusion.” There is evidence that, in the three cases studied in this paper, a vortex supplied the low-pressure center, occlusion and cold front to the “instant occlusion”. Abstract Three vortices in a polar air stream are analyzed using detailed mesoscale observations and conventional synoptic data. In their mature stages, the vortices exhibited wind, temperature and precipitation patterns similar to the larger extratropical cyclones that form on the polar front. Each of the three vortices interacted with the polar front to form an “instant occlusion.” There is evidence that, in the three cases studied in this paper, a vortex supplied the low-pressure center, occlusion and cold front to the “instant occlusion”.