text: Count the mana values of all other spells you've cast this turn before Call Forth the Tempest resolved, including any spells that you've cast due to Call Forth the Tempest's cascade abilities. It doesn't matter whether those spells resolved; you only need to have cast them. Conversely, if you copy a spell without casting it, you won't include that copy's mana value in the amount of damage Call Forth the Tempest deals.