Thinking upon it, its an emiitter "box" that make the weather,(like they had in TS2) here is the link to help give you a better idea, I think thats kinda what you are looking for to lead you in the right direction.
Let me know if this will work for you...
Witch: Just cause you may think I don't know what I'm talking about does not mean that it may not help some one else!!!
http://www.customsims3.com/smf/index.php?topic=2369.msg19813#msg19813