Data from meteorological gauging stations, pilot balloons and tethered balloons within Aburra valley, in Antioquia, Colombia are used to study the linking and coupling between free-atmosphere winds and internal valley winds on February 24th 2007. At the beginning of the morning, winds inside valley were weak and followed The direction of topography, so that they had almost 90° difference in comparison with above wind direction (blowing from east). Some hours later, as the radiation and the vertical turbulence processes began, inner valley winds were strongly affected by the presence of free-atmosphere winds so they appeared to be perfectly coupled with outer circulation. The observed data show that, in certain conditions, pressure-driven channeling and downward momentum flux can be used to explain wind circulation inside the Aburra valley.