17 January 2024
The likelihood of heatwave conditions is high in the coming weeks, while the risk of stormy conditions and hail is significant in the medium term.
Conditions for rain and stormy weather look favourable in the latter half of January over eastern parts of South Africa, including eastern parts of Limpopo, the whole of Mpumalanga, KwaZulu-Natal, far eastern parts of the Free State and northeastern parts of the Eastern Cape.
The reinforcement of tropical low-pressure systems north of Madagascar may channel tropical moisture from central Africa eastwards, with only small amounts of tropical moisture moving southwards over Namibia and Botswana.
“This will result in very little or no rain over central to western parts of the country until at least the end of January, but likely until deep into February,” says Johan van den Berg, an independent agricultural meteorologist.
“Isolated rain showers may occur in the Northern Cape, North West, most of the Free State, and the western parts of the Eastern Cape and Limpopo. However, it will be only light precipitation and it will be very hit-and-miss.”
Heatwave conditions
Van den Berg says temperatures will be very high in areas where little rain is expected, with heatwave conditions predicted especially in the Northern Cape and western parts of Limpopo, as well as western parts of North West, the Free State and the Eastern Cape.
In the winter rainfall region, very little rain – only light precipitation over the coastal areas of the southern Cape – is expected until at least the end of January.
Maximum temperatures will be very high, especially in the central to western parts of the Western Cape. In the Hex River Valley, for example, temperatures of 35-42°C are expected in the next three weeks, at least, with only a few days with temperatures below 35°C.
This also applies to the West Coast (in places such as Vredendal), the Cape Winelands and adjacent districts such as Paarl, Robertson and Ceres, the Overberg and southern Cape (places such as Caledon and Swellendam), as well as the Klein Karoo near Oudtshoorn and Laingsburg.
“Heatwave conditions with temperatures more than 3-5°C warmer than normal for five consecutive days could be recorded in the next at least three weeks. The hottest areas, however, will be the West Coast and wine country.”
Stormy conditions and hail
Although less rain is expected in the coming weeks in the central to western parts, many stormy conditions are forecast.
The heat can cause strong lifting of air. This can rapidly absorb smaller amounts of tropical moisture into the atmosphere, which can quickly cool and form light rain but also hail.
“In the eastern parts, especially KwaZulu-Natal and Mpumalanga where more rain is expected, very large and intense hailstorms may occur with even very heavy rain over smaller areas,” says Van den Berg.
“Cut-off low-pressure systems and supercells can still occur due to the heat over the interior, tropical moisture moving southward, especially over Zimbabwe, and cooler air from the southern Indian Ocean. The Drakensberg is also a significant source that stimulates the lifting of moisture and resulting stormy conditions.
“In the short and medium term, there is still a fairly significant risk of storms and hail for agriculture.”
