Over the past few weeks, certain parts of South Africa experienced disruptive rain as well as cloudy weather, widespread showers, and thundershowers, despite the country being in the summer season.
According to the weather service, La Niña is responsible for the country experiencing some uncharacteristically chilly summer days.
“We have been experiencing above-normal rainfall conditions as expected with the La Niña state as measured by ENSO [El Niño-Southern Oscillation]. It is not abnormal for [La Niña] to happen, however, it is expected considering that it’s under summer,” Saws forecaster, Lehlogonolo Thobela said during an interview on eNCA.
South Africans, Thobela cautioned, can brace themselves for a rainy Christmas weekend.
“We have a 60% chance of showers and thundershowers on Christmas day. We expect the central and eastern parts of the country to experience isolated showers and thundershowers, [where it will be] scattered over Gauteng, the eastern parts of North West, south-western parts of Limpopo, the south-western parts of Mpumalanga [as well as] the western parts of KwaZulu-Natal,” he said.
These weather patterns are expected to result in localised flooding of susceptible settlements, roads, and low-lying areas, difficult driving conditions and traffic disruptions as a result of significant falls and lower visibility, as well as wet roads at times.
Rainfall can also be expected on New Year’s Day.
“With [La Niña] happening, most conditions seem to be prone to more rainfall and heavy rainfall. The precipitation levels are showing to have rainfall occurring all throughout the third or fourth of January next year so it looks like it will be a blessed new year,” Thobela continued to say.
La Niña weather patterns
According to the World Meteorological Organisation (WMO) La Niña has developed for the second consecutive year and is expected to last into early 2022, influencing temperatures and precipitation.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, namely winds, pressure and rainfall.
It usually has the opposite effects on weather and climate as El Niño, which is the warm phase of the so-called ENSO.
But even with mounting data and improving computer models, El Niño, La Niña and the Southern Oscillation remain difficult to predict.