Animation Software

[tonsofpcs]

I need a free animation program that can take a few 5-10 frame looping animations and mask each one with a moving vector or hand drawn raster (either one, or just erasure even, but preferably vector masks) and layer them. Any OS, preferably Windows XP. Any ideas?
Basically, I need something for weather forecasts for our student-run TV station; I figure I can make a layer of looping cloud animation, a layer of looping rain, a layer of snowflakes, etc. all at 50% opacity or so with some gaps between particles over a base image and then just animate a mask on them or animate an outline for them.

[tinyvillager]

Hmm,it would be hard to find an all in one solution,especially freeware.

For a freeware vector graphics program i highly recommend Inkscape
 http://www.inkscape.org/

And then maybe a freeware animated gif creator
http://www.snapfiles...h.x=0&search.y=0
 

[tonsofpcs]

Here is a sample of what we want to do:
http://tonsofpcs.com/gfx/samples.html (note the base maps are just screen grabs from a TV channel near my home, we will be using our own for the regions and layering the images as appropriate, also note the animation there is a very simple one that I created to show an example)
I have personal software that I can use to pregenerate the animated layers so that in our production environment, they need only to create the masks or cut the layers.  If the masks can animate as well, that would be great.

[tonsofpcs]

Update:  Someone suggested I try http://www.synfig.com/ .  It is currently very unstable on Windows, but it does what is needed, although it needs to be obfuscated via layers and layer groups with a luma key on a polygon for the mask and different blend methods.  Something else would be better, but for now it runs stable via colinux so I will set up an installer to use that for now.