Over the course of her life, Ororo Monroe has been trained as a juvenile thief, worshiped as a goddess, and hated as a mutant. Since Charles Xavier enlisted her to join the X-Men, Storm has grown as a warrior and as a leader.Marvel Source
Her control over the climate has been honed through constant training and numerous battles, and her arsenal of elemental powers, from shattering lightning strikes to freezing winds, make her a force of nature to be feared and respected.
Thundering Tempest do not crit and is "spirit free". So, if you will focus this spell, maybe Hammer, AoE Improve? Ball lightning crits, but is "spirit dependent". Maybe Edge of Infinity + Spirit Regen. It's all about what u will focus. It's my opinion!
Any good ideas? I haven't really found better ones yet.
Solid build, you just need change the Artifacts. =) +1