During the next few days, there will be two periods with scattered to widespread thundershowers.
These will focus mostly on the central to eastern parts while the northern to western interior is expected to remain dry for the most part. Temperatures will on average be higher than the norm for this time of the year over the northern and western interior where dry conditions are expected, but towards the southeast it should be cooler than the norm on average.
The following is a summary of weather conditions during the next few days:
• General:
o The central to southern and eastern parts of the country will receive normal to above-normal rainfall during the next few days.
o The western and northern interior will be dry according to current forecasts.
o The northern to western interior will be warmer than normal while the rest of the country is expected to experience near-normal temperatures. o Strong southeasterlies are possible over the southwestern parts from Friday (13th) to Monday (16th).
• Rainfall:
o Scattered thundershowers will develop over the interior of the Western Cape and Garden Route on Wednesday (11th) and Thursday (12th).
o Scattered thundershowers will occur over the central to southeastern parts from Wednesday (11th) to Friday (13th), including the Eastern Highveld from Thursday (12th). Rainfall may be associated with cloudy, cooler spells over the southeastern parts.
o Some residual thundershowers are expected over the Eastern Highveld and KZN on Saturday (14th).
o Sunday (15th) should be dry over the interior according to current forecasts. o Scattered thundershowers will develop over the central to southeastern parts and Eastern Highveld from Monday (16th), becoming more widespread over the central parts by Tuesday (17th).
o Current forecasts indicate a possibility of significant rainfall over the Free State and into the eastern parts of the Eastern Cape and KZN by Tuesday (17th).
o Light showers will occur along the Garden Route on Sunday (15th) according to current forecasts.
o The western to northwestern half of the Northern Cape as well as most of Limpopo will remain dry throughout according to current forecast.
• Temperatures:
o It will be hot for this time of the year over the northwestern half of the Northern Cape, with maximum temperatures reaching the upper 30s by early next week.
o The southeastern parts (especially from the escarpment to the coast) will remain cool as a result of an onshore flow through most of the period.
o It will be cloudy and cool with showers or thundershowers over much of the Eastern Cape by Thursday (12th).
o Given somewhat wetter conditions over the maize-production region, maximum temperatures will be somewhat lower than last week while minimum temperatures will be somewhat higher.
o Maximum temperatures over the western maize-production region will range between 24 and 30 °C. Minimums will be in the order of 15 - 20°C.
o Maximum temperatures over the eastern maize-production region will range between 22 and 29°C (lower temperatures by Friday and early next week) while minimums will be in the order of 10 - 15°C (slightly warmer than last week).
Overview of expected conditions over South Africa during the next few days
An upper-air trough will move across the country between Wednesday (11th) and Saturday (14th), bringing widespread thundershowers over the southeastern parts and also most of the Western Cape interior. Another trough will develop in the southwest and start moving into the country early next week. The second system is also expected to bring rainfall to the interior. Both systems will be associated with a high-pressure system to the south, feeding cooler, moist air into the southern to eastern parts, keeping the southeastern half of the country relatively cool.
Conditions in main agricultural production regions (11 - 17 March)
Maize production region:
It will be partly cloudy and mild to warm with cooler conditions, associated with more widespread rain conditions, on Friday (13th) and early next week. Scattered thundershowers will develop over the entire area until Friday (13th). On Saturday (14th), thundershowers will be confined to the eastern parts of the region. Scattered thundershowers are again expected by early next week, following drier conditions on Sunday (15th). Maximum temperatures over the western maize-production region will range between 24 and 30°C. Minimums will be in the order of 15 - 20°C. Maximum temperatures over the eastern maize-production region will range between 22 and 29°C (lower temperatures by Friday and early next week) while minimums will be in the order of 10 - 15°C (slightly warmer than last week).
Cape Wine Lands and Ruens:
It will be cloudy to partly cloudy with scattered showers or thundershowers over the Boland, Karoo and Garden Route on Wednesday and Thursday (11th / 12th). It will initially be warm to hot over most parts, but somewhat cooler during the remainder of the period. It will become cool and cloudy with showers over the southern parts by Sunday (15th) when it will become hot over the West Coast and Swartland until Monday (16th). Strong southeasterlies are possible over the southwestern parts during the weekend into early next week.
Possible extreme conditions - relevant to agriculture
According to current model projections (GFS model) of weather conditions during the coming week, the following may be deduced:
• Some thundershowers over the central to southern and southeastern parts of the country on Wednesday (11th) and Thursday (12th) may become severe.
• Strong southeasterlies over the southwestern parts, especially during the weekend, may be conducive to the development and spread of wild fires where vegetation is dry.
• It will be very hot over the Orange River Valley by Sunday (15th) and Monday (16th).
• Some thundershowers over the Free State, eastern parts of the Eastern Cape and KZN may become severe by Tuesday (17th) according to current forecasts. This forecast has a long lead time - and therefore is less reliable.
