Towering Thunderhead

A cylinder of roiling clouds appears, shot through with punishing winds and sheets of lightning. This spell creates an enormous mass of dark clouds that provide concealment as fog cloud. Powerful and contrary currents of wind inside the cylinder have the effect of a wind wall spell. Movement within the cylinder is hampered; entering an affected square costs 2 squares of movement. You can see and move normally within your own towering thunderhead spell (though your ranged attacks are hindered as much as anyone else's). Any sonic or electricity spell of 7th level or lower cast by a creature within a towering thunderhead is automatically empowered (as if affected by the Empower Spell feat, but with no adjustment to the spell's level or casting time). Spells already affected by Empower Spell don't gain this benefit.
 

You conjure a massive, roiling thunderhead in a 40-foot-radius, 60-foot-high cylinder centered on a point within range. The storm churns with lightning, heavy winds, and swirling clouds. The thunderhead creates the following effects for the duration:   Obscuring Clouds: The area is heavily obscured, as per the Fog Cloud spell. You can see normally within your own thunderhead.   Howling Winds: The area is affected by wind wall-strength gusts. Ranged weapon attacks that pass through or are made within the thunderhead are made with disadvantage, and Medium or smaller flying creatures cannot enter.   Hampered Movement: The area is considered difficult terrain; every 5 feet of movement costs 10 feet of speed. You can move normally within your own thunderhead.   Spell Empowerment: Any Sonic or Electricity spell of 7th level or lower cast by a creature inside the thunderhead is automatically Empowered. A spell cannot benefit from this effect more than once.   At Higher Levels. When you cast this spell using a higher level spell slot, the radius increases by 10 feet and the height increases by 20 feet for each slot level above its base level. Additionally, if cast as an 11th or 12th level spell, increase the level of Sonic and Electricity spells that are empowered to 8th level or lower.