The transition from slightly viscous to viscosity‐dominated steady‐state, compressible, small‐disturbance flow is studied in the framework of the linearized Navier–Stokes equations. The classical picture of independent modes for vorticity, pressure, and temperature disturbances is preserved at all disturbance wavelengths down in the molecular scale. Particular transitions do, however, occur within the pressure mode itself, causing the governing equations to display new and qualitatively different features at the smaller disturbance wavelengths.