You gotta trust me on this Tempest thing, I played one. More like "temptation". Just throw in shocking grasp cantrip and it's fine. Jesus, the Arcana domain let's you select two wizard cantrips and plop them under wisdom based cleric spells.
I'm not quite sure what you mean by "trust me on this Tempest thing". You are provably wrong and others have already pointed this out. Also, why would you waste your ability maximizing the damage on Shocking Grasp when you could be using it on Thunderwave and Shatter?