Intense Spring cut-off low expected to affect large parts of South Africa over weekend

Numerical weather prediction data indicating 24-hour accumulated rainfall for Sunday. Source: Global Forecast System, NCEP

Numerical weather prediction data indicating 24-hour accumulated rainfall for Sunday. Source: Global Forecast System, NCEP

Published Sep 21, 2023

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South Africans have been warned to brace for another possible significant storm system over the weekend and early next week, following the recent damaging coastal storm surge.

The SA Weather Service (Saws) on Thursday said a cut-off low-pressure system is expected to develop along the west coast of South Africa from Saturday night.

“Cut-off lows are notorious for causing widespread severe weather such as flooding, heavy rainfall and severe thunderstorms. Widespread showers and thundershowers can be expected across western, central, and southern South Africa, particularly from Sunday onwards,” Saws said.

“However, notable uncertainty exists regarding the position and spatial distribution of the cut-off low at this current time, and further analysis will be required.”

Light rain is expected along the Garden Route of the Western Cape as well as the coast and adjacent interior of the Eastern Cape on Saturday.

Isolated to scattered thundershowers are expected to develop from the afternoon over the interior, extending from the eastern parts of the Northern Cape to the western Free State and later the interior of the Eastern Cape.

“The cut-off low will rapidly intensify by Sunday as it gets displaced northwards. It is expected to enter the country's western interior, where it will result in widespread thundershowers and rain over parts of the Western Cape, Northern Cape, Eastern Cape, and southern Free State. The Western Cape, Northern Cape, and western areas of the Eastern Cape may experience severe thunderstorms where bursts of intense rainfall may cause flash flooding.”

Strong to gale-force winds and very rough seas of 4 to 6m are also expected along the coastal areas on Sunday and Monday.

Cold conditions are expected over the western and southern parts of the country from Sunday, including the central parts on Monday, with a possibility of light snowfall over the north-eastern high-lying areas of the Eastern Cape and Lesotho on Monday.

Numerical weather prediction data indicating 24-hour accumulated rainfall for Monday. Source: Global Forecast System, NCEP

“On Monday, the cut-off low will move to the southern coast, developing a so-called scorpion’s tail, which will bring about further widespread and heavy rainfall over the southern parts of the Western Cape and the southern parts of the Eastern Cape,” Saws said.

@vox_weather_girls 🚨Early WEATHER ALERT for HEAVY RAIN and STRONG winds this weekend and early next week #weatherforecast #thunderstorms #heavyrain #southafrica #cutofflow #strongwinds #flooding ♬ Calm Beat - Pasha Velchev

The cut-off low is expected to move away from the country on Tuesday.

Cape Times