I get the feeling that something good is going to happen.
何か - something
いいこと - something good
起きる - to happen, to occur
予感がする - to have a feeling / to have a hunch
何かいいことが起きるような予感がする - I get the feeling that something good is going to happen. もしくは I have a feeling that something good is going to happen.
虹を見て、何かいいことが起きるような予感がした - When I saw the rainbow, I got the feeling that something good was going to happen.
I saw a beautiful rainbow in the sky, so I have a hunch I'm in for something good.
この場合、次のような言い方ができますよ。
ーI saw a beautiful rainbow in the sky, so I have a hunch I'm in for something good.
「綺麗な虹を見たので、何か良いことが起きる予感がする」
to have a hunch で「〜という予感がする・気がする」
ご参考まで!