  Recent supernovae (SNe) observations have motivated renewed interest in SN
shock breakouts from stars surrounded by thick winds. In such events the
interaction with the wind powers the observed luminosity, and predictions
include observable hard X-rays. Wind breakouts on timescales of a day or longer
are currently the most probable for detection. Here we study the signal that
follows such events. We start from the breakout of the radiation mediated
shock, finding that the breakout temperature can vary significantly from one
event to another ($10^4 - 5 \times 10^6$ K) due to possible deviation from
thermal equilibrium. In general, events with longer breakout pulse duration,
$t_{bo}$, are softer. We follow the observed radiation through the evolution of
the collisionless shock which forms after the breakout of the radiation
mediated shock. We restrict the study of the collisionless shock evolution to
cases where the breakout itself is in thermal equilibrium, peaking in
optical/UV. In these cases the post-breakout emission contains two spectral
components - soft (optical/UV) and hard (X-rays and possibly soft
$\gamma$-rays). Right after the breakout pulse X-rays are strongly suppressed,
and they carry only a small fraction of the total luminosity. The hard
component becomes harder and its luminosity rises quickly afterwards, gaining
dominance at $\sim 10-50 \,t_{bo}$. The ratio of the peak optical/UV to the
peak X-ray luminosity depends mostly on the breakout time. In terms of
prospects for X-ray and soft gamma-ray detections, it is best to observe
100-500 days after explosions with breakout timescales between a week and a
month.
