Radiation-hydrodynamical multi-group simulations of SN 1987A have been
performed to model the shock breakout of the supernova, and the evolution
of the emission from the ejecta during the subsequent 3-4 months. The
emission has been compared with the bolometric light curve, as well as
individual optical and IUE bands. The best models have energies in the
range 
ergs, and the agreement with
observations is better than in earlier, flux-limited diffusion calculations
for the same explosion energy. The color temperature during shock breakout
agrees with earlier calculations, but the structure of the outermost ejecta
does not show the pronounced density spike present in earlier results.
Such a spike is a result of incorrect radiative transfer. The maximum
velocity of the ejecta in the new models (i.e., 30,000-40,000 km
s 
) is similar to that indicated by Mg II 
2800 in early
IUE spectra.