Winter Rainfall Over the Interior of South Africa During Extreme Dry Years

It is hypothesised that during extreme dry years rainfall over the interior of southern Africa will increase due to an equatorward shift of the circumpolar westerlies. Examination of extreme wet and dry years during the wet spell of the 1970s and the dry spell of the 1980s shows that this was the case. Cloud cover, rainfall and the degree of regularity of cloud occurrence increased in a manner commensurate with a northward displacement of the westerlies. In addition, midwinter maximum and minimum temperature fields underwent small but distinctive variations. The results appear to hold only for extreme years.