The flame stability map defining the regime of existence of a counter-flowing laminar partially premixed methane-air triple flame has been determined using OH planar laser-induced fluorescence (PLIF). The stability limits were determined through the observation of flame merging and flame extinction, a function of rich and lean equivalence ratios, and mean axial strain rate. Relatively quantitative OH species profiles and Rayleigh scattering profiles have been measured for three flame conditions. Axial flow velocity profiles, and nozzle exit velocity profiles have been determined for two of the three conditions using 1-D laser Doppler velocimetry (LDV). The diffusion flame extinction axial velocity profile has been measured, and the local extinction axial strain rate has been determined to be 710 s(-1).