Pour Down Power across the Island (Downpour Drenches the World)

If you meet the elemental threshold for "Powerstorm," can the target spirit pay for and repeat the same power multiple times?
No, they can't.
The elemental threshold on "Powerstorm" allows the target spirit to repeat up to three different power cards.
The spirit Downpour Drenches the World is worded differently, and may repeat the same Power card. Similarly, when used in solo, "Gift of Twinned Days" may (and often must) Repeat the same Power twice.
(Discussion elsewhere) Tags: Repeat, Powerstorm, Downpour Drenches the World, Pour Down Power across the Island (Downpour Drenches the World), 1 more...
If you Forget a Power Card partway through resolution, do you continue resolving it? (E.g., if you gain a Major Power with "Entwined Power" and then Forget "Entwined Power.")
Yes, finish resolving the current use of the Power, along with any immediately-triggered instructions to Repeat the Power (e.g., via Relentless Gaze of the Sun using its "Relentless Punishment" special rule). The Power Card is no longer in play though, so you no longer gain the benefits of its Elements towards its own elemental thresholds and cannot Repeat it later in the turn with a "once this turn" Repeat option (e.g., via "Powestorm").
Tags: Forgetting, Repeat, Entwined Power, Draw Towards a Consuming Void, 11 more...

If a Special Rule cares about Elements, when does it check your Element total?
Each time you use the ability. If you gain or lose Elements throughout the turn, these special rules may become stronger or weaker.
If the special rule has a limited number of uses (e.g., Swiftness of Lightning), you can only use it again if you haven't used it more than your current Elements would allow. The total number of Elements you have had earlier in the turn doesn't matter.
Tags: Elements, Lightning's Swift Strike, Downpour Drenches the World, Swiftness of Lightning (Lightning's Swift Strike), 1 more...