  High resolution spectra of postoutburst novae show multiple components of
ejected gas that are kinematically distinct. We interpret the observations in
terms of episodes of enhanced mass transfer originating from the secondary star
that result in the formation of discrete components of circumbinary gas and
accretion onto the WD that trigger nova outbursts. In this picture the
concordance between absorption line velocities and emission line widths in most
novae occurs as a result of the collision of the expanding nova ejecta with a
larger mass of surrounding circumbinary gas. One implication of this model is
that much of the accreted gas remains on the WD, leading to a secular increase
in WD mass over each outburst event. Alternative scenarios to explain nova
spectral evolution are possible that do not invoke circumbinary gas and a
possible test of different models is proposed.
