A storm in a dream usually mirrors emotional turmoil that's been building somewhere in your life -- tension you can feel coming but haven't addressed directly. Whether the storm is frightening or oddly exhilarating in the dream often reflects whether you feel ready to face what's building, or still bracing against it.
Immobility of a slow celestial body is more efficient than the dynamism of a quick one, even though they have the same strength. - Picatrix (Andalusia, ~1000.AD)