Just one point of clarification, as some readers may wonder how the vortex, apparently so tiny, can interact with the main flow so effectively.
The photographs (and aren't they rather lovely) only show the central core of the vortex. As the temperature drops with radially reducing pressure this results in dewpoint temperature occuring at some radius under the conditions in which the photos were taken. Within the resulting core, condensation is visible.
The actual vortex is somewhat larger in diameter than that apparently seen in the photos.