Somewhere (out) there

"Somewhere there" without a preposition (over, up, etc.) is extremely casual.

It's gotta be there somewhere!

It's gotta be somewhere there!

Somewhere there's a solution to this problem is common, but "there is" is a completely different usage.

Thanks Avangi. Which would you use in this context:

Somewhere there/out there we will leave him.

Antonija
What's the difference between somewhere out there and somewhere there?

The answer is somewhat context-dependent. Generally speaking, though, the word "out" accentuates the idea of distance between the speaker and the location referred to, and/or emphasises that the location may be anywhere within a large geographical area.

Antonija Somewhere there/out there we will leave him.

Well, you make me rethink my original answer a bit.
"There" in this context refers to a previously mentioned or previously described area, region, location, etc.
"Somewhere there" is an unspecified point within that area.
"Somewhere out there" is an idiom which sometimes emphasizes the

AntonijaWhat's the difference between somewhere out there and somewhere there?

out. Not inside. Outdoors. Out in the world.

Suppose that I lost my keys. I am talking to someone inside my house.

somewhere in there: I think they are in that drawer. In fact, I'm sure they are somewhere in there.
so

Thank you Mr Wordy.