I need your help again- snow on the ground?

[Cocohoney]

Is it doable? I have Photoshop elements 8, this picture (last one, I promise!) I would like to do 3 things to-

Turn it to night
Age it
Add snow on the ground

It's a daylight shot and I want to make it night (have done this with previous pic thanks to the tutorials someone pointed me to), but this time I want the pic to be sepia and I want to add snow on the ground (and maybe falling too if that looks any good).

SO apart from being unsure how to do ground snow, I am also unsure how to order these. I am thinking I should do snow, sepia, dark- what do you think?

It's been a great and steep learning curve, but boy am I beginning to wish I hadn't started this!

 

[swanseamale47]

Really we need to see the pic, if theres grass it shouldn't be too difficult to lighten it.
I'd do the snow first then turn it to night.

 

[Cocohoney]

I know, I can't post the picture though as it is for school. I don't have grass, they are standing on tarmac. I think I might have to forget the snow on the ground.

 

[swanseamale47]

You may be about to select the ground and lighten it, filter distort diffuse glow might or might not help.
EDIT make sure you reset your colour boxes on the left to default before running diffuse glow (hit D on the keyboard0