Stop weather strats dead in their tracks.
Roster
Moves
Moves
Moves
Moves
Moves
Moves
Strategy
Altaria is the center point. With Cloud Nine, weather teams lose their advantage, turning the battle into a neutral playing field. Altaria is meant to be bulky and remain on the battlefield for long enough for the weather to fade. Mega Altaria is on the table should it get to that point where weather is no longer a factor, or if you need Mega Scrafty, you can pop that instead. Altaria won't mind the lack of item because it's main use is its ability. This team is also decent into TR, since most of them are also fairly slow.
Lead Options
Altaria + Scrafty, Sableye + Altaria, Garchomp + Altaria, Sableye + Metagross
Win Conditions
Use Altaria to shut down weather while buffing the bulky hard hitting pokemon on your side. Garchomp and Metagross are the main win cons.
Threats & Bad Matchups
I haven't played this team too much, but from what I've seen, your biggest threat is hard decision making. Knowing when the weather is a nonissue to let go of Altaria, understanding how to get around the faster pokemon without losing Altaria too early, and playing too fast and loose with Meta or Chomp. Sometimes you just gotta take the L from turn 1.