Towards the development of an optimum stability index for forecasting convective weather activities over Nairobi

Abstract

Upper air data extracted from the 2300z (2.00 AM lOCAL TIME) radiosonde soundings for the Nairobi station during 1988, 1989 and 1990 has been used to develop a number of stability indices which could be useful in forecasting convective weather activities (in particular, rain or showers and thunderstorms) in the Nairobi and surrounding area. The development of the indices was based on a number of factors including the environmental lapse rate of temperature, the effect of diurnal surface heating, the moisture content of the lower level of the atmosphere and the verticle extent of the moist layer. A relationship was established between the computed induces' values and the probability of occurrence or non-occurrence of convective weather activities over the area on the successive days that followed the soundings