Relatively favorable conditions for isolated to scattered thundershowers will be present over the central parts of the country initially, remaining in place until the weekend.
By early next week, there will be a drastic increase in rainfall over the summer rainfall region, associated with a deepening upper-air trough according to current forecasts. Current forecasts favor the Highveld for significant totals during the early part of the (next) week. A cold front may result in widespread rain over the winter rainfall region by the weekend. The system will also once again spread cold air over the southern parts of the country, but current forecasts don't indicate any widespread frost over the interior until at least the middle of next week.
The following is a summary of weather conditions during the next few days:
• General:
o The maize-production region should continue to receive above-normal rainfall.
o The southwestern interior is expected to remain dry for the most part, but the southwestern winter rainfall region will receive normal to above-normal rainfall.
o On average, temperatures will be near normal over the country tending to be slightly more below normal over the winter rainfall region.
o Partly cloudy and warm conditions will dominate across the country from Thursday (9th) with isolated to scattered thundershowers over the central interior - especially around the eastern Northern Cape.
o Current forecasts suggest cloudy, cool and wet conditions early next week over the central to eastern parts, including the maize-production regions- with possible significant daily totals over the Eastern Highveld into northern KZN and along the coast of KZN (still a long lead time making it somewhat more uncertain). Forecasts suggest possible strong winds along the KZN coast as the system moves out on Tuesday (14th).
o It should clear over the interior by late Tuesday (14th) according to current forecasts.
o Cold fronts will result in rain or showers over the winter rainfall region. Light showers are possible on Friday (10th) and Saturday (11th) with more widespread showers and possibly significant falls in the mountainous areas by Sunday (12th).
• Rainfall:
o Isolated thundershowers are expected over the Eastern Highveld on Wednesday (8th). Light showers are possible over the coast of KZN and adjacent interior as well as the eastern escarpment.
o Thundershowers will become scattered and relocated to the central interior (eastern Northern Cape, northern half of the Eastern Cape, Free State and southern North West on Thursday (9th) to Saturday (11th).
o Light showers are possible over the southern winter rainfall region on late Friday and Saturday (10th/11th).
o Thundershowers will relocate to eastern North West, Gauteng and northeastern Free State by Saturday (11th).
o Widespread rain and thundershowers are possible over the northeastern half of the country, excluding the northern parts of Limpopo, according to current forecasts, by Monday (13th) and Tuesday (14th).
o Widespread showers are possible over the winter rainfall region and Garden Route with strong westerly to southwesterly winds by Sunday (12th).
• Temperatures:
o Hot and windy conditions are possible over the western interior on Thursday (9th) to Saturday (11th).
o It will be very hot over the Lowveld on Sunday (12th).
o Cool to cold conditions in the south will be replaced by progressively warmer conditions until the weekend.
o It will once again become colder over the southern parts by Sunday (12th), continuing into next week.
o Maximum temperatures over the western production areas will be in the order of 20 - 27°C - lowest temperatures expected early next week. Minimum temperatures will be in the order of 11 - 17°C.
o Maximum temperatures over the eastern maize-production region will range between 15 and 27°C (the lower temperatures will be present early next week) while minimums will be in the order of 8 - 13°C.
Overview of expected conditions over South Africa during the next few days
The first few days will see scattered thundershowers over the western half of the central interior, due to an influx of moisture from the east around the Indian Ocean Anticyclone as well as some tropical moisture spilling in from the north. A frontal system will move into the southwestern parts by the weekend, bringing rain to the winter rainfall region and Garden Route while resulting in falling temperatures over the southern interior. The associated upper-air trough is expected to deepen over the western to central interior from Sunday, promoting widespread thundershowers over the central to eastern parts according to current forecasts, associated with cloudy and cool conditions over much of the summer grain production areas.
Conditions in main agricultural production regions (8 - 14 April)
Maize production region:
The period will start out partly cloudy and mild with fairly windy conditions. It will gradually heat up and the wind will become lighter towards the weekend. Isolated to scattered thundershowers are possible over the south-western parts of the region until Saturday. Thundershowers should move into the rest of the area by Sunday (12th) and could become scattered to widespread on Monday and Tuesday (14th) according to current forecasts, when cloudy and cool. It should clear by Wednesday (15th). Maximum temperatures over the western production areas will be in the order of 20 - 27°C - lowest temperatures are expected early next week. Minimum temperatures will be in the order of 11 - 17°C. Maximum temperatures over the eastern maize-production region will range between 15 and 27°C (the lower temperatures will be present early next week) while minimums will be in the order of 8 - 13°C. There is currently no indication of widespread frost over any part of the region.
Cape Wine Lands and Ruens:
The first few days will be mild to warm with light winds. It will become cloudy with light showers by Saturday. Widespread showers with windy and cold conditions are possible on Sunday (12th). It will clear by Monday (13th) and become sunny and warmer again.
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:
• Hot (and at times) windy conditions are possible over the western interior until Saturday (11th). Where vegetation is dry, these conditions may enhance the probability for the development and spread of wild fires.
• It will be very hot over the Lowveld on Saturday (11th) and Sunday (12th).
• It will be cool to cold (and windy) over the southern interior by from Sunday (12th). This may be accompanied by wet conditions also over the Eastern Cape and eastern parts of the Western Cape interior. The cold conditions may adversely affect small stock in the region.
• Persistent cloudy, wet and cool conditions early next week may favor the occurrence of fungal plant pathogens.
• Thundershowers over Gauteng, western to southern Mpumalanga, northeastern Free State and into northern KZN may become severe on Monday (13th) and Tuesday (14th) according to current forecasts.
• Significant daily rainfall totals are possible over the Highveld of Mpumalanga and northern KZN as well as the Wild Coast and Sun Coast on Monday (13th0 and Tuesday (14th).
