In non-premixed combustion, edge flames can form as a region of flame recession. These so called negative edge flames occur when local gas velocity from burned products moves through the flame edge, representing a local extinction process that may occur for example during vortex-induced extinction of a non-premixed flame sheet. The influence of heat carried by advection into the flame edge as well as the so called "negative edge speed" are studied through numerical simulation. Scalar dissipation rates along the stoichiometric contour are examined for several flow conditions. The flame edge, defined as the point where the temperature along the stoichiometric contour equals the temperature just prior to 1D global extinction, is found to form at a scalar dissipation rate higher than the 1D scalar dissipation rate. This increase in necessary scalar dissipation for extinction has a linear trend with the advective heat flux through the extinction point for all cases where radial diffusion is negligible. Furthermore different values of velocity through the flame edge are obtained for cases with the same extinction scalar dissipation. No single value of "negative edge speed" is apparent as temperature gradient also plays a role in flame extinction.