discussion ; adding Sound effects such as thunder or rain in aftereffects

Sound editing tools in After Effects are very limited. You can use Dynamic Link to edit and modify a soundtrack in Adobe Audition or render the video and do the sound editing in Premiere Pro. If you choose Audition, you'll get a proxy video rendered and running right in the app so you can see exactly what is going on. Jumping to Audition (edit menu with an audio track selected) or editing the audio in Premiere Pro sounds like more work than editing audio in After Effects, but it takes less time, and you'll have full control over the sound. Where the stereo is centered, graphic EQ, and even surround sound if you need it. Inside After Effects, you're basically stuck with levels and left or right pan.

If you must use After Effects, you'll end up with a very amateurish audio track, which may be all you want.