5 March 2024
The chance of rain is limited until at least March 16, with rainfall of 10-20mm or less possible over northeastern parts, while heatwave conditions are set to persist.
The rainfall expected until mid-March is expected in parts of Limpopo, Mpumalanga and KwaZulu-Natal. From the middle of the month, these rains may spread to the Free State, North West and Gauteng.
“For the entire Northern Cape, inland Eastern Cape, and the northern inland of the Western Cape, very little or no rain is expected for almost the whole of March,” says Johan van den Berg, an independent agricultural meteorologist.
The chance of heavier rain over the central to eastern inland improves in the last few days of March. But very little rain is expected over the western inland.
Predictions show that 20mm or more may occur from around March 24 to 28. This forecast is early and still uncertain. “It is at least positive that models are beginning to indicate better rainfall conditions,” says Van den Berg.
“With the slow weakening of the El Niño system, rainfall conditions are still expected to remain below average, although there is a better chance of rain starting to develop.”
Late winter rainfall season?
Meanwhile, it is expected that the rainy season in the winter rainfall region may start later than usual due to the weakening of the El Niño system. “The chance of rain increases during strong El Niño events.”
For now, the winter rainfall region is experiencing more frequent cold fronts accompanied by light rainfall. This trend is expected to continue in March with cold fronts expected around March 12, 15, 19, 23 and 25. Rainfall is generally expected to be less than 5mm.
Climate change or El Niño?
Regarding the rainfall and the cut-off low at the beginning of this week, Van den Berg says it is difficult to distinguish between climate change and the effects of El Niño when trying to identify the precise cause of extreme conditions in the Western Cape. Hail was seen in many places, including the Mossel Bay and George areas. Thunderstorms, which are unusual for the Western Cape, also occurred in several places.
Van den Berg says most global warming occurs in the oceans because water can store much more energy than, for example, soil. This causes stronger low-pressure systems with stronger storms and more rain, as well as stormy conditions.
“One of the characteristics of the past few seasons is the high occurrence of cut-off or intense low-pressure systems that have occurred mainly over the western and southern coastal areas and inland.”
For example, it was a cut-off low-pressure system that moved south of the country around March 4, affecting southern and southeastern parts of the Western Cape. The heaviest rainfall was in Somerset West, where 38mm was measured. Bredasdorp received 26mm, Robertson 21mm, Hopefield 22mm and Stellenbosch 17mm.
“The direction of movement of a cut-off low-pressure system and where it will develop is very difficult to predict because it moves independently of the larger systems. This is especially difficult when it moves so close to the coastline because it can change direction very quickly and move over land,” explains Van den Berg.
“Although the rainfall amounts were less than predicted, the cut-off low-pressure system still caused very windy conditions over large areas, as well as the occurrence of hail in the Garden Route and Langkloof.”
Very high temperatures
Very high temperatures are expected to continue until after mid-March. This applies to almost the entire summer rainfall region. Temperatures above 40°C could occur from March 9 to 13 over the Northern Cape in places like Upington and Augrabies. In western summer grain-producing areas, in places like Schweizer-Reneke, Delareyville, Bothaville and Hoopstad, temperatures will range from 35°C to 40°C from March 7 to 16.
More centrally, including places like Klerksdorp and Kroonstad, temperatures will vary from 33°C to 38°C. Even eastward over areas like Bethlehem, Reitz and Standerton, temperatures will be above 30°C.
Warm conditions are also forecast for Eastern Cape inland areas in places like Jansenville, Graaff-Reinet and Cradock, where temperatures could exceed 35°C. In Limpopo, places like Lephalale (Ellisras) and Messina may experience temperatures up to 40°C until mid-March.
Heatwave conditions are also predicted from March 9 to 12 over parts of the winter rainfall region. Places like Paarl, Worcester, Vredendal and Piketberg can experience temperatures above 40°C. Further east, places like Caledon, Swellendam and Riversdale may record temperatures of up to 35°C. Cold fronts are expected to cause more frequent rapid temperature drops over the Western Cape.
