Drier winter looms for Western Cape as persistent south-easter signals concern

The Western Cape may be heading for a drier-than-usual winter, with meteorologists warning that persistent weather patterns driving strong summer winds could also limit rainfall in the months ahead.

Speaking on Cape Talk, Dr Christien Engelbrecht, a lead scientist for long-range forecasting at the South African Weather Service, said the unusually strong and prolonged south-easterly winds experienced this summer are linked to large-scale pressure systems over the South Atlantic.

High-pressure system influencing rainfall

Engelbrecht explained that the South Atlantic high-pressure system plays a key role in determining how cold fronts reach the Western Cape during winter.

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“When the Cape does not receive the typical amounts of rainfall it should, the South Atlantic high-pressure system influences how cold fronts make landfall,” she said.

Under such conditions, cold fronts tend to track further south, reducing the number of systems that move over the province’s winter rainfall region.

Strong south-easter driven by pressure gradient

While south-easterly winds are common during summer, Engelbrecht noted that what has stood out in recent weeks is their persistence and strength.

“This is not only due to the high-pressure system itself, but rather the combination of a deep trough along the west coast and the high-pressure system, which creates a strong pressure gradient,” she explained.

That pressure gradient has resulted in sustained, strong south-easterly winds not only over the Western Cape, but along much of the Cape south coast, extending as far east as Gqeberha.

Seasonal forecast raises alarm

Looking ahead, Engelbrecht said the latest seasonal forecast for the Western Cape is ‘not very promising’.

“For the extreme south-western parts of the Western Cape, the eastward coastal regions and adjacent interior, forecasts for April, May and June are indicating below-normal rainfall,” she said.

She cautioned that seasonal forecasts do come with uncertainty and are updated regularly but added that the outlook for the onset of the winter rainfall season is concerning.

Dam levels already under pressure

The warning comes as dam levels in the Western Cape continue to decline following the summer months, currently sitting at around 65% capacity — lower than at the same time last year.

While no widespread water restrictions have yet been imposed, several municipalities across the province are already preparing for, or implementing, precautionary measures in anticipation of a drier winter.

Meteorologists say fewer cold fronts making landfall over the province would translate into reduced winter rainfall, placing additional strain on water supplies if the forecast holds.

For more information, listen to Engelbrecht using the audio player below: