ΔE 8.6, close: similar, with a visible difference side by side. Stormy Sea is a little lighter, more saturated than Unforgiven Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Stormy Sea is a little lighter, more saturated than Unforgiven Green.
The same difference applies the other way round: Unforgiven Green is a little darker, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Unforgiven Green on the colour wheel See Stormy Sea on the colour wheel
All matches: Unforgiven Green equivalents · Stormy Sea equivalents