Snow 3.0 Tweaks

Hello, I found the great snow tutorial on this site and was wondering if I could have some questions answered about tweaking it.

#1 I would like to have the snow start at the top of the stage instead of just appearing covering the entire stage.

#2 This may be a simple question, but why is it that the snow always appears above anything else on the stage? I wanted to make some gradients on the edges of the stage so the snow would sort of vanish in the sides and fade in from the top instead of just appearing and disappearing on hard edges. It seems though that the snow is always above anything on the stage.

#3 Is there a way to make the snow speed up part way through a timeline. Meaning I have the snow effect running and then I would like it to speed up without reloading the entire actionscript. I have tried it by placing a new action script but the snow that is already falling disappears and new snow appears at the faster rate. I would like to seamlessly make the snow start to move faster and faster.

I am a quick learner but I don’t have a ton of actionscript training. If someone could just point me in the right direction on these questions I am sure I could figure them out.