Storm

A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather. It may be marked by strong wind, thunder and lightning (a thunderstorm), heavy precipitation, such as ice (ice storm), or wind transporting some substance through the atmosphere (as in a dust storm, snowstorm, hailstorm, etc).

Storms are created when a center of low pressure develops, with a system of high pressure surrounding it. This combination of opposing forces can create winds and result in the formation of storm clouds, such as the cumulonimbus. Small, localized areas of low pressure can form from hot air rising off hot ground, resulting in smaller disturbances such as dust devils and whirlwinds.
Storms are not unique to Earth; other heavenly bodies with a sufficient atmosphere (gas giants in particular) also undergo stormy weather. A famous example is the Great Red Spot on Jupiter. Though technically a hurricane, it is larger than the earth and has been raging for at least 340 years, when it was observed by astronomer Galileo Galilei. Neptune also had its own lesser known Great Dark Spot.

In September 1994 Hubble telescope using Wide Field Planetary Camera 2 imaged the storms on Saturn, generated by upwelling of warmer air, similar to a terrestrial thunderhead. The east-west extent of the same-year storm was equal to the diameter of Earth. The storm was observed earlier in September 1990 and acquired the name Dragon Storm.