I have a tornado animation that has a pretty low velocity, and I'm getting lines in the fluid source that I can't seem to shake. They are still visible in the render as well. As I increase the source from points values, the lines grow larger, but still remain. All points have the same density.

Can you please elaborate on that?

Although judging by what you just said, maybe you have some stagnant smoke, dude to low vel.
Maybe what you could do is in your smoke/pyro solver, in the Advection tab >> Advection method, the default is set to Trace

You could maybe try using other advection methods like Trace Midpoint,HJWENO, etc

Maybe that might help

Thanks for the reply! I'm fairly certain the lines are a product of too high of a division size, so what I am seeing is the voxel pattern. I'm finding it difficult to sim at a low enough division size on my work station. If I add enough noise to the fluid source, then the lines becomes turbulent enough that they are not visible.

Substeps appear to fix the problem