Bombogenesis: because "thundersnow" has already been beaten into the ground, as is the way of things today. (I think it happened around midnight. You're already playing yourself if you say "thundersnow" — like how your eyes can't roll far enough when someone says "snowpocalypse," and you can't beat them severely enough if they say "snowmageddon.")
Haven't sorted out exactly how it works yet — "bombogenesis" being derived from "cyclogenesis" (naturally) and both, I think, describing the set of necessary conditions rather than the event itself. Whatfuckingever. I know it's rarer than radium, reported on average just 6.3 times per year in the whole US. I know it's said that a guy in Bucks County, PA got hit by snowlightning this evening (all in all, my guess is lightningsnow is more survivable — either way, this is less dramatic than both double-rainbow…). And I know that for the second time this winter I was walking down First Ave and I saw, then heard, lightning and thunder, while snow blasted around us. Figuring the world is dying and/or my luck is changing I bought lottery tickets immediately. On First Ave, of course. I'll cut you in, don't worry.