This study examines the characteristics of tropical cyclone (TC) turbulence and its related predictability implications. Using the Fourier-Bessel spectral decomposition for convective-permitting simulations, it is shown that TC turbulence possesses different spectral properties in the azimuthal and radial directions, with a steeper power law in the radial-wavenumber than those in the azimuthal-wavenumber direction. This spectral difference between the azimuthal and radial directions prevents one from using a single wavenumber to interpret TC intensity predictability as for classical homogeneous isotropic turbulences. Analyses of spectral error growth for a high-wavenumber perturbation further confirm that the spectral growth is more rapid for high azimuthal wavenumbers than for the radial wavenumbers, reaching saturation after ~9 hrs and ~18 hrs for the azimuthal and radial directions, respectively. This result highlights the key difficulty in quantifying TC intensity predictability based on spectral upscale error growth for future applications.