Convective heat-transfer measurements were made over and downstream of a narrow band of large distributed roughness near the leading edge of a NACA 0012 airfoil at zero angle of attack. The roughnesses tested were idealized representations of those found in initial glaze-ice accretions. The heat-transfer measurements were obtained using the infrared-spectroscopy method in which the model was heated by infrared heat lamps and the surface temperature was measured with an infrared camera. The measurements were taken at Reynolds numbers of 0.75x10 ⁶, 1.25x10⁶, and 2.25x10⁶. In addition to the nominal 0.1% tunnel turbulence, measurements were also taken with levels raised to 0.5% and 0.95% using turbulence generating grids, in order to simulate the higher turbulence levels seen in icing tunnels. The heat-transfer rates over and immediately downstream of the roughness were higher than the predicted smooth-wall turbulent values. However, far downstream of the roughness, the heat-transfer rates had transitional values which were less than the predicted turbulent values. The heat-transfer enhancement due to the roughness was observed to increase with increasing Reynolds number. The elevated freestream turbulence intensities were shown to have negligible effect on heat-transfer rates downstream of the roughness. On the clean model, the elevated freestream turbulence did not affect the heat-transfer rates until the turbulence levels in the boundary layer near the wall became elevated.