Yes, CYCLONIC is a Scrabble word!

Letter values in Scrabble US: C 3, Y 4, C 3, L 1, O 1, N 1, I 1, C 3.

Is it a valid word?

CYCLONIC is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

of or relating to or characteristic of the atmosphere around a low pressure center
of or relating to or characteristic of a violent tropical storm

Not playable in Scrabble US: CYCLONICAL.