A storm is traditionally a disturbed atmospheric state on a planet. However, storms in space can take on many different types of characteristics. Storms are often accompanied by strong winds, thunder, lightning, and precipitation (rain, snow, etc).
On Earth, the Florida Keys were often threatened by hurricanes and other such storms.
In 2151, on an unknown planet, the crew of the Enterprise (NX-01) had to take shelter in a cave to avoid a storm. (ENT: "Strange New World")