Rain and snow are possible over the central parts of the country around 13, 16 and 17 August. A stronger cold front later in the week could also bring snow to the mountainous areas of the Western, Eastern and Northern Cape, as well as Lesotho.
By Alani Janeke, senior journalist at African Farming and Landbouweekblad
After rainfall of up to 52mm and 70mm over parts of the summer rainfall region last week, forecasts indicate that more rain could fall in these areas this week. The chances of rain on Wednesday and Saturday are good for the eastern Northern Cape, Free State, Gauteng, northern Eastern Cape, Mpumalanga and KwaZulu-Natal.
“Heavy rainfall could again occur in places, and from 13 to 17 August, snow could fall over parts of the Drakensberg,” says independent agricultural meteorologist Johan van den Berg.
“A fairly strong frontal system will affect the country again from 20 August. Weather models currently indicate that widespread snow is possible over much of the mountainous areas of the Western, Northern and Eastern Cape, as well as in Lesotho.”
Conditions may become slightly warmer at times in August, increasing moisture levels in the air. “Sharp temperature drops with higher moisture content can lead to more rain and snow. Cold air can hold less moisture than warm air, so it must release it in the form of rain, snow or freezing rain.”
More Rain Over Winter Rainfall Region
As frontal systems move across the winter rainfall region, further rain is possible in parts of the area on Friday and Saturday, as well as from 19 to 21 August and during the last few days of the month. Precipitation is expected to be light on Friday and Saturday, but rain could be slightly heavier in places from 19 to 21 August, Van den Berg says. “High rainfall levels are not expected over the grain-growing areas, such as the Swartland and Rûens, until at least the end of August. Light rain may occur over these areas.”
Low minimum and maximum temperatures, combined with cloudy conditions, should keep plant water consumption relatively low. “To date, more rain has fallen during the winter months than initially predicted, but drier conditions could now begin to set in,” he adds.
“Groundwater conditions remain fairly favourable, although most soils have limited water storage capacity. However, regular light rainfall may help reduce the impact of the expected decrease in rainfall over the coming weeks on crop production.”
Also read: Keep small livestock safe during severe cold
Frost and Cold Snaps Could Return
Weather models indicate that minimum temperatures over the central to southern interior will remain low for the rest of the month. The frontal system expected next week may cause temperatures to drop sharply once more.
Minimum temperatures below or near freezing could occur from 19 to 22 August across most of the Free State, adjacent parts of Mpumalanga, southern Gauteng, southern Northern Cape, southern KwaZulu-Natal and the interior of the Eastern Cape. In the Western Cape, areas such as Ceres, the Hex River Valley, Robertson and Clanwilliam may experience temperatures below freezing from 19 to 23 August.
“The big question remains until when very low minimum temperatures and frost could still occur, especially in warmer production areas such as Limpopo and the Northern Cape,” Van den Berg says.
He says that current synoptic conditions show frontal systems remain very active along the west coast, suggesting the cold conditions may persist.
The chances of further very cold conditions in the northern parts of Limpopo are small, he says. In the Northern Cape, however, low minimum temperatures and frost may persist until very late in the season – as late as September, and in the eastern Northern Cape possibly until October.
“The low temperatures experienced so far may help plants become slightly less sensitive to cold damage through hardening off (as they acclimatise to colder conditions) and slowed growth. However, the risk of frost damage remains high for new growth.”
