Any of the special effects from weather is a decent payoff for spending one card (especially two threat removed). But the real value here is that combining one Weather Goddess with Storm's innate Weather Control ability lets your whole team take advantage of Thunderstorm to attack, and still switch to Blizzard or Hurricane before the villain turn. Using the "call for action" rule lets you use one of your weather change effects on the first player's turn and the other weather change on the last player's turn, regardless of where Storm is in the player order (assuming she's in hero form, of course).