Weather Effects

Are there any plans to add maps with dynamic weather effects? Even if the effects can't be dynamic, I'd still take a map like Hard Rain from L4D2.

Having things like heavy rain showers or infrequent lightning strikes could add a level of unpredictability to matches. The rain would make it more difficult to hear and see things temporarily, whereas a lightning strike could light up the stage, blowing up any stealth attempts from either side.