The paper presents some results of atmospheric turbulence and mean flow structure measured during the Phoenix Air Flow Experiment (PAFEX-I) in January 1998. The experiment was aimed at observing and probing the development of convective and nocturnal boundary layers of the complex terrain of Phoenix. The measurements were made with tethered balloon instrumented with two meteosondes, which measure wind velocity, temperature and relative humidity. Nocturnal boundary layer measurements show that the mean flows induced by the katabatic (drainage) flow are the order of 1 m/s, and the flow changes direction with height significantly. Direct measurements reveal some interesting properties of drainage flows with regard to their origin, stability and speed. The turbulent measurements by sonic anemometer and a network of 44 measuring sites around the valley were also utilized to analyze the general flow properties. The observations were used to develop some new concepts on complex terrain circulations