From Bulbapedia, the community-driven Pokémon encyclopedia.
Thunder Meadow (Japanese: かみなりこうげん Thunder Plateau) is a Friend Area. It is in the Plains Area, and has a capacity of eleven Pokémon, most of them Electric-type. It can be bought from Wigglytuff for 1000 Poké.
Thunder Meadow has a rough landscape, consisting of rough grass, with what seems to be a dead tree that was struck in two by thunder near the entrance. There is also a small fissure at the end of the cliff. The sky shows a storm on the horizon with thunder clouds.
A meadow covered in thunderclouds. Besides Electric-type Pokémon, a startling variety of other Pokémon live here.