Ruby Storm's spells are almost all red (Manamorphose is a red/green hybrid, so it counts as red too), which makes Hydroblast excellent here: it can counter nearly any spell they cast, such as Desperate Ritual, Seething Song, Big Score or their card-flow sorceries, or destroy Goblin Anarchomancer, which is red-green and therefore red. It cannot destroy their lands, which are colorless or green-producing non-spells, and it cannot hit the green-only Thornscape Familiar. Pyroblast is left in the sideboard because it only affects blue spells and permanents, and Ruby Storm's main deck has none. Envelop answers their sorcery-speed engines like Glimpse the Impossible, Reckless Impulse, Wrenn's Resolve and Seize the Storm, so it picks up the spells Hydroblast would otherwise have to spend a card on. Toxin Analysis and Krark-Clan Shaman are too slow or situational against a combo deck trying to assemble a storm kill. Prioritize applying early pressure since Ruby Storm has little defense, and hold up Hydroblast for their ritual effects when possible.