South Africa braces for wet summer and heatwaves amid La Niña uncertainty

South Africa could be in for a wet summer with potential flooding in parts of the country and higher-than-normal temperatures being expected, according to South African Weather Service meteorologist, Lehlohonolo Thobela. 

“We are expecting above-normal rain for the central and eastern areas of the country. So, we might experience more heavy rains as well as thunderstorms that may result in heavy rain and flooding for the eastern provinces,” Thobela told the Mail & Guardian.

Despite the rain, high temperatures are expected across the country during the summer months, he said. 

Snow fell in various parts of the country last weekend, closing important routes, leaving motorists stranded and killing livestock and crops. 

Heavy snowfall was recorded in Gauteng, the Free State, Mpumalanga, KwaZulu-Natal and Eastern Cape. It caused an extensive traffic backlog between Free State and KwaZulu-Natal, leaving thousands of motorists trapped for up to 13 hours on one of the country’s busiest routes. 

“The snow was due to a cold environment as well as enough moisture in the area. These conditions resulted from a weather system called a cut-off low as well as a cold front that was east of South Africa. 

“These weather systems caused a drop in freezing levels, a drop in temperature, rain, as well as a lot of moisture that resulted in snow,” Thobela said.

A cut-off low is a pressure system that develops in the upper air as it cuts off from its normal westerly flow. It is associated with weather systems that develop at the surface or lower levels of the atmosphere, making it more potent, according to Kanyisa Makubalo, a forecaster at the South African Weather Service.

Researchers are studying if these events are happening more frequently and with more intensity, Neville Sweijd, the director of the Alliance for Collaboration on Climate and Earth Systems Science, previously told the M&G.

“Daytime temperatures are expected to recover quickly from Sunday into Monday across eastern South Africa,” the weather service said in a statement.

El Niño and La Niña are the warm and cool phases of a climate pattern that brings warm or cooler, wetter weather, respectively. It is commonly referred to as ENSO.

“ENSO is currently still in a neutral state and is predicted to weaken further. However current predictions are mixed in whether it will weaken towards a La Niña state during our next summer season. 

“It is advised to monitor the ENSO system, as significant changes in the system may occur after the winter period due to increased prediction skill,”  the weather service said. 

“With a potential La Niña event on the horizon affecting the summer season, and early indications of above-normal rainfall over most of the summer rainfall areas during [October, November and December], the initial outlook is positive for good rainfall in summer. 

“There is an exception however for the Limpopo region which still indicates below-normal rainfall that can be expected going into the early summer period. Mostly drier conditions are still expected over the country during spring,” it said.

The weather patterns are expected to affect agriculture.

“Below-normal rainfall is forecasted for most parts of the country in the early spring and mid- to late-spring seasons, with the exception of some areas in the Free State province. 

“Conversely, above-normal rainfall is expected in most parts of the summer rainfall regions, except for the Limpopo province, during the early summer season. This above-normal rainfall forecast for these summer rainfall regions will likely have a positive impact on crop and livestock production,” the service said.

But Limpopo is expected to have below-normal rainfall in early summer.

The weather service recommended that farmers “implement soil and water conservation measures, proper water harvesting and storage techniques, establish effective drainage systems, and adopt other appropriate farming practices”.