These vortices are high-pressure systems that can migrate to the equator. They remain stable due to the Coriolis forces that cause the storms of the northern hemisphere to rotate clockwise due to the rotation of the planet. (These storms are not like hurricanes on Earth that rotate counterclockwise because they are low pressure systems.) However, as the storm drifts towards the equator, the Coriolis effect weakens and the storm disintegrates.