Despite the general applicability of classical Ekman theory, individual observations of wind veering in the planetary boundary layer seldom exhibit the typical spiral turning with height. This study attempts to assess the reasons for these deviations from theory which occur not only as large fluctuations in time but also as significant differences in mean profiles from one location to another.

Two well documented cases of tradewind disturbances are studied. One disturbance developed into Hurricane Carla (1961) while the other failed to intensify. Initially the two cases appeared to be very similar but on closer inspection the flow patterns in which the disturbances were embedded proved to have significant differences. This paper describes these differences.