In this paper we analyse how the presence of inertia (Forchheimer form-drag) affects the steady free convective boundary layer flow over an upward-facing horizontal surface embedded in a porous medium. The surface temperature is assumed to display a power-law variation, x(n), with distance from the leading edge, x. It is shown that there are three distinct cases to consider: it ( 0.5, n = 0.5 and 0.5 < n less than or equal to 2. In the first case inertia dominates the flow near the leading edge, but its effect wanes downstream. The boundary layer is self-similar in the second case with the resulting profiles being dependent on the strength of the inertia effect. In the third case, inertia effects grow with increasing distance from the leading edge, and the boundary-layer thickness is greater than when inertia is absent.