Predicted H line widths for our analytical blast wave models (curves) compared with observed H I Paβ widths from Banerjee et al. (2014; crosses). The upper curves and data points correspond to the broader line component arising in the forward shock; the lower set of curves in our models arise from the reverse shock, which we identify with the narrow component in the line widths of Banerjee et al. (2014). Four models are shown, corresponding to different combinations of ejected mass, explosion energy, and circumstellar density profile (see the text).