ΔE 14.6, fair: the same colour family, but not a straight swap. Turquois (Phthalo) is a little lighter, more saturated, warmer than Thunderhawk Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Turquois (Phthalo) 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 Turquois (Phthalo) on the colour wheel
All matches: Thunderhawk Blue equivalents · Turquois (Phthalo) equivalents