The National Weather Service had earlier said the combination of two weather systems from the polar and sub-tropical jet streams would produce a "potentially historic" storm.
Glenn Orton, a researcher at the Jet Propulsion Laboratory in Pasadena, California, who has led the analysis of the merged storm, admits that Jupiter's weather is still only dimly understood.
This is the so-called jet stream, the fast river of air that helps drive our weather, which interacts with the storm's updrafts to create a spinning column of air.