How cool would it be if storm cells randomly popped up and moved across the map. Fighters and bombers would have to divert around large cells to avoid the unfavorable flying conditions within them. Sometimes you'll face a light drizzle, other times you're presented with hail and strong winds, almost impossible to fly in.
However, once you get your head out of the clouds (pun intended), the scale of this in implementation, frame rates, and effects on game play make this idea not much more than a dream.