Hi, well i have been asked about my storm affect and some people wanted me to post a tutorial on how to make it.
Open up photoshop
1.first of all open a new file file>new or (ctrl + n) and choose the size you want.
2.now go to the backgroud layer and go filter>render>clouds
3.then hit ctrl + f a few times in order to get the background you want.
4.now after you selected the one you want, hit ctrl + u in order to get the saturation menu window pop up, and select the color you want. the darker it is the better the effect usually turns out.
You should have something that looks like this

5.now make a new layer, ctrl+shift+n and hit ok, creating a new layer
6.now go to filter>render>clouds
7.then filter>render>difference clouds
8.then hit ctrl+f a few times and pick the one you like, its always good to pic the ones with only a few concentrated areas of white, gives a better effect,
9.now hit ctrl+l to get the levels screen and play around with it inorder to get the areas of white to become thin and showing, usually the stats 50, .50 and 150 work fine, a few tiems you have to change them
10.now set the layer to linear dodge
then you will have something that looks like this

now repeat the folowing steps 5-10 2 more times or so, make sure you don't pick the same difference clouds more then once lol
now you have your layers move your slide into image ready by hitting shift+ctrl+m
11.now make sure your animation and layers windows are open, by going to window>animation then window>layers
12.now hide all the layer except for the background layer (by making sure that the eye is unchecked in the layers window)
13.duplicate the layer about 15-20 times or so
14.now go and choose random ones and check the eye on one of the lightening layers, make sure you dont have the same layer checked in a row, and press play and look at the effect if you don't like it try a different order.
now you have your effect, which you can add to. for example i added some rain, a figure that pops on the screen after a lightening usually, my name which changes effect, a boarder, and an extra layer for the origin clouds in order to increase there effect. Have fun with it and it will turn out great.
My final effect is my sig