Duplicate the wave layer, flip it horizontally, and position them back to back. Here, we’ve placed the waves further apart than they need to be for clarity. Now bring the two waves together and paint on the Layer Masks to merge them until they appear to form one unified crest.
To make the isolated rain storm, make a feathered selection outlining the shape of the rain. Activate the Background layer and press Ctrl/Cmd + J to copy and paste the selection on to a new layer.
Apply a Pattern Overlay layer style to the new layer. Choose any style and click OK. We are going to apply a ready-made style from the Styles palette. Load the Image Effects styles if they are not already in the Styles palette.
With the pattern layer still active, click the rain style swatch from the Styles palette to apply the effect, then double-click the Pattern Overlay sub-layer in the Layers palette to access the pattern settings. Change the Scale to 360 per cent to make the rain larger and more visible.