Using airborne radiation thermometer measurements and air dropped expendable bathythermographs, the near-surface thermal structure of a section of the Gulf Stream northeast of Cape Hatteras was monitored before and immediately after the passage of Hurricane/Tropical Storm Dennis in August 1981. The passage of Dennis increased the average horizontal separation between the surface and subsurface Gulf Stream fronts from about 1 to 19 km. This increase in separation between the two fronts was apparently caused by wind-driven cross-stream advection in the mixed layer.