might not:
She might not have seen you.
The weather might not be fine tomorrow.
We might not have to wait because the bus is coming.
will:
Tommrow, I will go to the zoo.
1 more year. I will study abroad.
2 more weeks, I will go to the supermaket.
won't:
Tommrow, I won't go to the zoo.
1 more year. I won't study abroad.
2 more weeks, I won't go to the supermaket.