  All Type IIn supernovae (SNe IIn) show narrow hydrogen emission lines in
their spectra. Apart from this common feature, they demonstrate very broad
diversity in brightness, duration, and morphology of their light curves, which
indicates that they likely come from a variety of progenitor systems and
explosion channels. A particular subset of SNe IIn, the so called SNe IIn-P,
exhibit $\sim$100 days plateau phases that are very similar to the ones of the
ordinary hydrogen-rich SNe (SNe II). In the past, SNe IIn-P were explained by
the models of sub-energetic electron capture explosions surrounded by dense
extended winds. In this work, we attempt to explain this class of SNe with
standard red supergiant (RSG) progenitors that experience outbursts several
month before the final explosion. The outburst energies that show the best
agreement between our models and the data ($5\times10^{46}\,{\rm erg}$) fall at
the low range of the outburst energies that have been observed for SNe IIn
(between few times $10^{46}\,{\rm erg}$ and $10^{49}\,{\rm erg}$). Instead, the
inferred explosion energy of SN 2005cl is relatively high
($1-2\times10^{51}\,{\rm erg}$) compared to the explosion energies of the
ordinary SNe II. Our models provide alternative explanation of SNe IIn-P to the
previously proposed scenarios.
