A turbine stage includes a row of airfoils joined to corresponding platforms to define flow passages therebetween. Each airfoil includes opposite pressure and suction sides and extends in chord between opposite leading and trailing edges. Each platform has a contoured flow surface including a purge valley, an elevated bulge and a bowl. The purge valley has a maximum depth at an elevation equal to or greater than a nominal axisymmetric platform surface of the corresponding platform. The purge valley extending tangentially against a purge cavity wall and into the blend area and extending axially from proximate the leading edge of a first airfoil toward the suction side of the first airfoil, and toward the leading edge of a second adjacent airfoil to channel a purge flow. The elevated bulge adjoins the pressure side aft of the leading edge and the bowl adjoins the suction side aft of the leading edge.