ΔE 15.9, loose: different enough that you should pick on purpose. Cobalt Turquois is a little lighter, more saturated, warmer than Thunderhawk Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Cobalt Turquois is a little lighter, more saturated, warmer than Thunderhawk Blue.
The same difference applies the other way round: Thunderhawk Blue is a little darker, more muted, cooler.
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 Thunderhawk Blue on the colour wheel See Cobalt Turquois on the colour wheel
All matches: Thunderhawk Blue equivalents · Cobalt Turquois equivalents