  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 blastwave 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.
