  The inhomogeneous surface distribution of heavy elements is known to cause
periodic light variability of magnetic chemically peculiar stars. It is unclear
to what extent the same paradigm applies to mercury-manganese (HgMn) stars. We
aim to model the photometric variability of the HgMn star {\phi}Phe using
abundance maps obtained from high-resolution spectroscopy and to study how this
variability evolves with time.
  We compute a grid of ATLAS12 model atmospheres and the corresponding SYNSPEC
synthetic spectra. Interpolating within this grid and integrating the specific
intensity over the visible stellar surface at different rotational phases, we
obtain theoretical light curves of the star.
  We predict the variability of {\phi} Phe in the ultraviolet and in the
visible spectral regions with amplitude of the order of millimagnitudes, mainly
caused by absorption in lines of yttrium, chromium, and titanium. We also show
how this variability is affected by changes of the distribution of the heavy
elements over time.
  The main characteristics of the predicted light variability of {\phi} Phe
correspond roughly to the variability of the star observed with the TESS
satellite.
