  A nonlinear quantum-classical transition wave equation is proposed for
dissipative systems within the Caldirola-Kanai model. Equivalence of this
transition equation to a scaled Schr\"{o}dinger equation is proved. The
dissipative dynamics is then studied in terms of what we call scaled
trajectories following the standard procedure used in Bohmian mechanics. These
trajectories depend on a continuous parameter allowing us a smooth transition
from Bohmian to classical trajectories. Arrival times and actual momentum
distribution functions are also analyzed. The propagation of a Gaussian wave
packet in a viscid medium under the presence of constant, linear and harmonic
potentials is studied. The gradual decoherence process and localization are
easily visualized and understood within this theoretical framework.
