Storm Blue vs Thunderhawk Blue

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Thunderhawk Blue is a little darker, more muted, cooler than Storm Blue.

Can I use Thunderhawk Blue instead of Storm Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Thunderhawk Blue is a little darker, more muted, cooler than Storm Blue.

Can I use Storm Blue instead of Thunderhawk Blue?

The same difference applies the other way round: Storm Blue 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.