Fatshimetrie: South Africa braces for wet summer
The weather forecast for the summer season in South Africa is predicting a wet summer, with potential flooding in some parts of the country and higher than normal temperatures, according to South African Weather Service meteorologist Lehlohonolo Thobela.
According to Thobela, “We are forecasting above normal rainfall for the central and eastern parts of the country. As such, we may experience more heavy rainfall as well as thunderstorms that could cause heavy rain and flooding in the eastern provinces.” The forecast suggests a turbulent summer in terms of weather.
Despite the rain forecast, high temperatures are also forecast across the country during the summer months.
Over the weekend, heavy snowfall was recorded in various parts of the country, leading to the closure of major roads, stranding motorists and killing livestock and crops.
The snowfall was observed in Gauteng, Free State, Mpumalanga, KwaZulu-Natal and the Eastern Cape provinces. It caused major traffic jams between the Free State and KwaZulu-Natal, leaving thousands of motorists stranded for up to 13 hours on one of the country’s busiest roads.
Thobela said the snowfall was triggered by a cold environment and sufficient moisture in the region. The conditions were the result of a weather system called an upper-level trough and a cold front located east of South Africa.
A upper-level trough is a pressure system that develops in the upper atmosphere as it breaks away from its usual westerly flow. It is associated with weather systems that form on the surface or in the lower layers of the atmosphere, making it more powerful, according to Kanyisa Makubalo, a forecaster at the South African Weather Service.
Researchers are investigating whether these events are occurring more frequently and with greater intensity, as Neville Sweijd, director of the Alliance for Collaboration on Climate and Earth Sciences, previously told the Mail & Guardian.
“Daytime temperatures are expected to recover rapidly from Sunday to Monday in eastern South Africa,” the weather service said in a statement.
El Niño and La Niña are warm and cool phases of a weather pattern that bring warm or cooler, wetter weather conditions, respectively. It is commonly referred to as ENSO.
“ENSO is currently still in a neutral state and is predicted to weaken further. However, current forecasts are mixed regarding a possible strengthening towards a La Niña state during our upcoming summer season..
“It is recommended to monitor the ENSO system, as significant changes in this system may occur after the winter period due to an increase in predictability,” the weather service stressed.
“With the potential for a La Niña event on the horizon that will affect the summer season, and preliminary indications of above-normal rainfall in most summer rainfall areas during [October, November and December], the early outlook is favourable for a good summer rainy season.
“There is however an exception for the Limpopo region which still indicates below-normal rainfall expected at the start of the summer period. Predominantly drier conditions are still expected across the country in the spring,” it added.
The weather patterns are likely to influence agriculture.
“Below normal rainfall is forecast for most parts of the country in early spring and mid to late spring, with the exception of some areas in the Free State Province.
“In contrast, above normal rainfall is expected in most areas of the summer rainfall zones in the early summer season. These above normal rainfall forecasts for these areas of the summer rainfall zones are expected to have a positive impact on crop and livestock production,” the service added.
However, below normal rainfall is forecast for Limpopo in the early summer.
The weather service has advised farmers to “implement soil and water conservation measures, appropriate water harvesting and storage techniques, establish efficient drainage systems and adopt other appropriate agricultural practices” to cope with the weather conditions.