[thejeff]

Without modding, and off the top of my head, you could divine bless and Thunder Ward them on the first round so they fly to attack, then cast Storm and Wrathful Skies on the second round.

Of course, you can't use a Staff of Storms so it's harder to pull off.
Not quite as effective either, since they won't be able to fly to the next target once the first drops, but if you're relying on Wrathful skies to do the killing anyway. On the other hand, if you're relying on Wrathful skies to do the killing, you may not want them flying up right away. It's a delaying game at that point, so you'd want to hold them back as long as possible.