—Here we have analyzed the governing equations of reacting low Mach number flow ror plane premixed flame structures in non-unirorm flow fields given that the activation temperature of the mixture is large compared to the temperature of the remote reactants. An extinction mechanism is uncovered Tor flames with Lewis numbers less than one thal cannot be round through the use of activation energy asymptolics, a limit where the activation temperature of the mixture is large compared lo the burned gas temDerature.