You scream "TACTICAL FIREBALL, INCOMING!!!" and point at a spot within range. A small bright streak flashes from your pointing finger to a point you choose within range and then explodes into a small ball of flame.  Each creature in a 5-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 1d6+1 fire damage on a failed save, or half as much damage on a successful one. 

At Higher Levels. When you cast this spell when you are 3rd level or higher, the damage increases by 1d6+1, and again at 6th, 9th, 12th, 15th, 18th, and 20th levels.