CONTRASTING SYNOPTIC WEATHER EVENTS OVER SOUTHERN AFRICA IN THE DRY SUMMER OF 1983

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Abstract
Short-lived subtropical circulation systems which affected summer convection over the plateau of southern Africa during 1983 are studied. In the first case, tropical moisture was advected onto the plateau by weather systems originating in the Mozambique Channel. Westward movement in mid- January 1983 coincided with a surge of the Indian monsoon over the eastern escarpment. The circulation pattern supporting convection was a low level anticyclone over the southern Mozambique Channel in conjunction with a sharp upper westerly trough over the western escarpment. A contrasting drought event occurred in the second half of February 1983. A stationary upper westerly trough over the equatorial Atlantic Ocean increased upper level convergence and anticyclonic vorticity downstream over the plateau. According to outgoing longwave radiation (OLR) data the 1982–1984 drought over southern Africa reached maximum intensity with this event.