consistent.
For example, if you were standing at a bus stop with no buses in sight and I tell you to take the next bus, you wouldn't let a bus pass then take the second bus that comes. Same with the OPs example. If I told you to take the next left, you would take the immediately coming left, not skip the coming one and take the following one.
Most expressions, next = the immediately coming one.
When referring to days, next = not this coming one, but the following one.
Pointing out that 2 days from now is THIS Thursday is specific, and fine. Same with the OPs post, you could also say take THIS left turn.