A cloudy, cold spell of persistent rainfall is anticipated for some of the eastern provinces in the days ahead, driven by a developing upper-air cut-off low system.
This is according to Garth Sampson from the South African Weather Service (SAWS).
“In particular, the eastern part of Eastern Cape is expected to experience a significant chance of heavy rain and flooding today and tomorrow, where Impact-Based Warnings are already in effect,” said Sampson.
He added that at the current time, a well-developed upper-air trough, associated with coldness and instability, is in the process of intensifying over the south-western parts of southern Africa.
“SAWS is confident that, during the coming days, this system will further deepen and intensify, forming a cut-off low over the southern and central interior. Whilst much of the interior of the African subcontinent is currently rather dry, this system is expected to introduce a welcome rainy spell to some of the eastern provinces from today onwards, through to the middle of this coming week. However, this system is expected to shift progressively eastwards, resulting in mostly clear, rain-free conditions by Thursday.”
There is already a high likelihood of rainfall across much of the Eastern Cape province during today where level 2 as well as level 5 warnings are already in place for disruptive rainfall, leading to localised to widespread flooding, persisting overnight. Within the level 5 warning area, 100 mm (or more) of rainfall may occur within a 24-hour period, Sampson explained.
“For tomorrow, the heavy rain warning is escalated from level 5 to level 6. Rainfall during this period is expected to be mostly of a patchy nature, but generally less intense than the rainfall anticipated today and tomorrow over Eastern Cape.”
Sampson further added that sustained rainfall over a relatively large area will inevitably lead to the ground becoming saturated, resulting in overland runoff into river and stream systems, as well as heightening the risk of localised flooding.
“Under such circumstances, informal dwelling structures, especially those built of mud bricks will be particularly prone to sudden collapse. The public would also be well-advised to keep jackets and blankets close at hand, as the weather will remain very chilly over the abovementioned provinces.”
