I'd just have a simple Thunderstorm Whammy, where you hear birds chirping with a sun shining, but quickly, a storm cloud moves with a Whammy inside of it, and then a big bolt of lighting zaps the player's score away, only to have the Whammy get struck by himself, before the storm moves away to the right. I'd perhaps have other weather-related Whammies, such as a tornado where a Whammy sucks up the players score before the Whammy crashes upward, a Flood Whammy where a gush of water drains the player's score away with the Whammy, and a Blizzard Whammy where the player's score gets covered in snow and then as it melts, the money melts with it too.
It's quite fitting as severe weather is real world Whammies that can cause a hike in insurance, and perhaps the Whammy could remark about "your insurance bill is about to take a hefty premium! Ha ha ha ha!"
