If you can hit with the first arrow, the others will follow.

Daily   ✦     Martial, Weapon
Standard Action      Ranged weapon

Target: One creature

Attack: Dexterity vs. AC, three attacks. If the first attack hits, you gain a +5 bonus to the second and third attack rolls. If the first attack misses, roll the second and third attacks normally.

Hit: 2[W] + Dexterity modifier damage per attack.

Miss: Half damage per attack.

Published in Player's Handbook, page(s) 113.