Help with boat wake filter

I just started using Filter Forge and I'm currently trying to make a boat wake filter. I'm making progress, but not quite getting what I'm looking for yet. Below is an image comparing the desired effect versus my current filter.

Right now I just have a single layer of noise that's been mirrored and blends out on the edge. I think I need a couple more layers of noise, but the main thing I haven't figured out is how best to make it not so straight on the edges. I want the edges to scale in and out a bit and have a harder edge like in the desired image.

I'll take any advice or tips I can get. Thanks!

Thanks Sharandra, that looks promising. I'll try that out.