  The winds of hot, massive stars are variable from processes happening on both
large and small spatial scales. A particular case of such wind variability is
'discrete-absorption components' (DACs) that manifest themselves as outward
moving density features in UV resonance line spectra. Such DACs are believed to
be caused by large-scale spiral-shaped density structures in the stellar wind.
We consider novel 3-D radiation-hydrodynamic models of rotating hot star winds
and study the emergence of co-rotating spiral structures due to a local
(pseudo-)magnetic spot on the stellar surface. Subsequently, the hydrodynamic
models are used to retrieve DAC spectral signatures in synthetic UV spectra
created from a 3-D short characteristics radiative transfer code.
