ΔE 15.7, loose: different enough that you should pick on purpose. Storm Blue is a little darker, more muted, cooler than Shyish Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Storm Blue is a little darker, more muted, cooler than Shyish Purple.
The same difference applies the other way round: Shyish Purple is a little lighter, more saturated, warmer.
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 Shyish Purple on the colour wheel See Storm Blue on the colour wheel
All matches: Shyish Purple equivalents · Storm Blue equivalents