We present simple analytical expressions for the predicted spectral and temporal behavior of the early afterglow radiation from gamma-ray bursts in radiative regimes intermediate between the adiabatic and the fully radiative solutions of the blast-wave hydrodynamic equations. Our expressions are valid as long as the relativistic electrons responsible for the observed synchrotron emission are in the fast-cooling regime and the blast wave is relativistic. We show that even a slight deviation from a perfectly adiabatic evolution results in significant changes of the temporal characteristics of the afterglow emission.