H2O: Combined Atmokinesis

Combined Atmokinesis is the term for when three mermaids combine their amplified powers, and they're able to control the weather. Cleo Sertori, Emma Gilbert and Rikki Chadwick used this for the first time when they got their augmented powers and were still under the full moon's influence to attack Lewis, who had come to check on them.

They created a massive electrical storm over Mako Island, the wind of which was measured to be over 200 km/h, making it the equivalent of a Category 4 Severe Tropical Cyclone.