  In this article we study a nonlocal Nambu--Jona-Lasinio (nNJL) model with a
Gaussian regulator in presence of a uniform magnetic field. We take a mixed
approach to the incorporation of temperature in the model, and consider aspects
of both real and imaginary time formalisms. We include confinement in the model
through the quasiparticle interpretation of the poles of the propagator. The
effect of the magnetic field in the deconfinement phase transition is then
studied. It is found that, like with chiral symmetry restoration, magnetic
catalysis occurs for the deconfinement phase transition. It is also found that
the magnetic field enhances the thermodynamical instability of the system. We
work in the weak field limit, i.e. $(eB)<5m_\pi^2$. At this level there is no
splitting of the critical temperatures for chiral and deconfinement phase
transitions.
