My dictionary lists /ˈkɑɹ.məl/, /ˈkɑɹ.ə.məl/, and /ˈkæɹ.ə.mɛl/ all as acceptable pronunciations.
The season come again for winter’s tales, I tell you one which my nurse told to me As watched I warily the swirling snows. “I’ll raise one up,” she swore, “of ghosts by night…”