Istanbul is bounded by the Black and Marmara Sea and divided by the 31-km long and approximately 3-km wide Bosphorus strait. Figures illustrate the horizontal wind patterns and convergence-divergence zones over Istanbul for morning, midday and evening. Northerly synoptic flows forced channeling through the strait affecting the eastern coast, including Goztepe, of Istanbul. Throughout the day, near-surface winds remained weaker above urban areas. Possible effect of urbanization on channeling can be also considered. Convergence zones formed at the boundary of the urban areas, which act as a barrier to the flow while convergence zones formed over urban areas. Divergence zone formed over Marmara Sea.