Shaman · talent ability, from Stormstrike

Stormstrike

123per cast

level 60 · before talents

Stormstrike

125 ManaMelee Range

Instant8 sec cooldown

Instantly strike for normal weapon damage and increase the damage you deal to the target with your next Lightning Bolt, Chain Lightning, or Earth Shock spell by 20% for 12 sec.

Talents that change it, each at full ranks:

Mental Dexterity +14.5 Tidal Focus +6.8 Thundering Strikes +5.8

Averages, counting crits and misses, with a typical weapon and no other gear or buffs, against a target your level. Talents at level 60. Worked out from the game's own data, the same way as the Foresight addon.