From Descent: Journeys in the Dark Second Edition Rules of Play -book:
2–6: Some dice also have a number on them, which determines how much Range a given attack has.
Even though Ranged attacks may target any space in the attacker's line of sight, the attacker must roll enough range on his attack roll in order to deal damage to the target. Starting with the space adjacent to the attacker (of his choice), count the number of spaces to the target space. This number is the distance between the spaces. The numbers rolled on the dice are the maximum range of the attack. If the total range obtained from the attack roll does not equal or exceed the distance between the spaces, the attack is considered a miss unless the range can be increased
Jain Fairwood rolls “3” Range on her blue attack die and “2” Range on her yellow power die, for a total of “5” Range. Since the Goblin Archer is only two spaces away, there is plenty of range for the attack to hit the target.