Rainfall expected for the WC

Rainfall predicted for the Western and Northern Cape provinces this week, is likely to have little impact in the longer term. Picture: South African Weather Service

Rainfall predicted for the Western and Northern Cape provinces this week, is likely to have little impact in the longer term. Picture: South African Weather Service

Published Jan 21, 2018

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Rainfall predicted for the drought-stricken Western Cape is likely to have little impact in the longer term. 

South African Weather Service spokesperson Hannelee Doubell said light to moderate rains (10 mm or less) were expected over the central and eastern parts of the Western and Northern Cape province today. 

“The rainfall prospects for Monday are, however, expected to be somewhat better, when the entire Western and Northern Cape region is likely to receive some rainfall, mostly in the form of showers and thundershowers,” Doubell said. 

The South African Weather Service however emphasised that rainfall will be predominantly light to moderate, possibly with some heavier falls occurring sporadically over the mountainous parts of Western Cape.   

An upper-air cut-off low was expected to develop seawards of the Western Cape over the weekend, moving over the Western Cape this week. 

“Cut-off low systems can often be efficient rain-producing systems. In extreme cases, cut-off lows can deliver heavy rain over a widespread area especially in the winter months,” Doubell said. 

However, given that the upcoming rain system is expected to be fairly weak, this particular system is not expected to have the capacity to deliver widespread, heavy rain.

“Some isolated, heavier falls, perhaps of the order of 30 mm, may well occur over some parts of the interior of Western Cape on Monday and Tuesday, when rain prospects for the region will be at their best,” she said. 

According to the service’s projected 24-hour rainfall fields generated by numeric weather modelling (NWP), it is only on Monday and Tuesday that rainfall prospects are at their best for the Cape Peninsula. 

"But even then, it will be unrealistic to expect much more than 10-20 mm per day for the Peninsula, Doubell said. 

Due to the light to moderate nature of the predicted rain over the next few days,  the overall ground moisture level is likely to increase measurably. 

“Evaporation will typically be negated by cool, cloudy to overcast conditions. Under such circumstances, sustained, elevated soil moisture could potentially lead to mudslides in susceptible areas,"  Doubell said.

The prevailing drought has significantly denuded surface vegetation in some areas, also contributing to an increased risk of washaways or mudslides in hilly or mountainous areas.

"The rainfall over the coming days over the drought-stricken areas will surely be greatly valued and appreciated. While this rainfall episode may result in some short-term relief, it will nevertheless have little impact in the longer term. 

"Much more rainfall is still required in order to sustain the Western Cape through the coming months.  

"Typically, for the winter rainfall region of the Western Cape the first winter rains occur in April and May, however, it is too early to speculate as to whether such rains will be experienced either earlier or later in the season," Doubell said.

WATCH: Cape Town is experiencing its worst drought ever and Day Zero is looming. Watch this video to find out what will happen if we reach Day Zero and what the City has been doing to prevent it.

 

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