It would have the same effect of chaining MST to Heavy Storm. While it destroys the card, the chain resolves and Heavy Storm/Lightning Vortex still resolve with their effects before being destoyed. The cards destroy themselves when they are sent to the graveyard, so it would be useless to use MST on either of these cards. Magic Jammer or Magic Drain would be better choices as they negate the effect of the Spell card. This is the important difference. MST, as stated previously, does not negate the effect of the spell card when chain to the activation of that spell card.