The important cases of cyclonic and anticyclonic circulations are discussed next. Therefore, wind shear in belts is cyclonic, while in zones it is anticyclonic. Near the poles are anticyclonic structures called polar vortices. It is associated with ridging, or anticyclonic flow. Like Jupiter's spot, Great Dark Spots are anticyclonic storms. It is associated with an area of maximum anticyclonic curvature of wind flow. Various processes can produce an anticyclonic tornado. Three long-lived anticyclonic features termed white ovals were observed in 1938. The system continued west for a few days at about next to an anticyclonic aloft. On the 23rd it became a tropical depression before executing an anticyclonic loop. Anticyclonic storms usually form around high-pressure systems. When conditions are heavily anticyclonic, there is less soaring during the day. They also confirmed that the Great Red Spot was anticyclonic. Before the heat wave, anticyclonic conditions prevailed across the UK. Jupiter's Great Red Spot is a well-known non-terrestrial example of an anticyclonic system.