Is Thryx, the Sudden Storm legal in Standard, Modern, and Commander?

Thryx, the Sudden Storm is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Thryx, the Sudden Storm

Q: What type of card is Thryx, the Sudden Storm?

Thryx, the Sudden Storm is a Legendary Creature — Elemental Giant. Its oracle text reads: "Flash (You may cast this spell any time you could cast an instant.) Flying Spells you cast with mana value 5 or greater cost {1} less to cast and can't be countered. *Even in their mountain fortresses, the Akroans have learned not to anger Thassa.* Power/Toughness: 4/5"