Ionospheric measurements of electron density, electron and ion temperature, and vertical drift made at the Millstone Hill incoherent scatter radar have been used to derive the neutral exospheric temperature and the thermospheric neutral wind speed along the magnetic meridian. These two parameters were used as input to a dynamic model for the neutral atmosphere over Millstone from which values of the zonal and meridional winds at 300 km were derived. Of 85 days of data available over the 6 year period 1970--1975, 21 days were geomagnetically active (daily average AE?300&ggr;). In analyzing the disturbed days, heating of the ions by the neutral winds, differences in the neutral density from MSIS model predictions, and electric field effects were taken into consideration. All disturbed days show three distinct effects, viz., enhanced nighttime temperatures, strong equatorward nighttime winds, and transition of the zonal winds from eastward to westward much earlier in the nighttime sector than usual. The strong equatorward winds transport high latitude heat away from the auroral zone. They usually are found to maximize after midnight and probably represent an extension to mid-latitudes of the 'midnight surge' seen at auroral latitudes (Bates and Roberts, 1977). In the daytime sector, some disturbed days exhibit poleward winds, which are not as strong as normal, but this does not seem to be a consistent feature.