In Chapter 269 of the Fairy Tail Manga. Juvia causes a storm across Tenrou Island.
It's visibly shown that the clouds are being drawn in rather than created. So KE is Valid here.
The diameter I'll be using comes from this calc. Making the Diameter 4,609.52 meters.
Storm clouds are 8,000 meters so that's the height we'll use.
Radius is 2,304.76 meters.
This makes the volume of the cylinder 1.33503e11 m^3.
This makes the mass 133,903,509,000 kg.
The timeframe in the anime is 7 seconds, making the speed 658.5 m/s.
The yield is 2.90320224e16 Joules, or 6.9 Megatons of TNT.
This makes most X784 Characters City Level