11 December 2023
The South African Weather Service predicts that the movements of three weather systems from today could lead to heavy rainfall, especially over the eastern part of South Africa on Sunday and Monday, with warnings of possible flooding.
The cause of the widespread rain, according to the weather service, will be a combination of three separate circulation systems over Southern Africa.
First, it is expected that an upper-air cut-off low will develop over the central interior in the latter half of the weekend.
Second, a surface trough is expected to start strengthening at the same time. “The combination of these two systems is well-known for having the potential to bring episodes of widespread, often heavy rain over Southern Africa,” says the weather service.
“What is crucial is that in this specific case, a third significant factor is expected to enhance the risk of heavy rainfall from the system.
“This factor is the anticipated influx of a stream of tropical moisture being drawn southwards over the central and eastern interior of South Africa, under the influence of the circulation associated with the surface trough and upper-air system respectively.” Tropical air is generally associated with heavy and widespread rainfall.
According to the weather service, “tranquil” weather conditions are expected until Sunday, with a limited chance of rain over the eastern provinces. The Western Cape and Eastern Cape are not expected to be affected by the systems.
Sunday and Monday
Weather conditions can significantly change from Sunday as the cut-off low moves over the northern part of the Northern Cape and disrupts conditions in the atmosphere, bringing widespread rain and thunderstorms.
Rain is expected over North West, the Free State, Gauteng, Mpumalanga, Gauteng, Limpopo, and, to a lesser extent, KwaZulu-Natal. “Heavy rain may occur over areas in these provinces, increasing the risk of floods and overflowing rivers.”
The weather will persist until Monday, and with groundwater being quickly replenished in certain areas, runoff and consequently flood conditions are possible. Weather conditions are expected to clear from Tuesday onwards.
The weather service will monitor the system and keep members of the public informed about it in the coming days.
