Possible severe thunderstorms for eastern North West and Gauteng, with possible flooding

The SA Weather Service (Saws) has issued a level 4 warning for possible severe thunderstorms in the eastern North West and Gauteng on Tuesday, with possible flooding. 

According to the weather service, models are showing areas of slow-moving thunderstorms that may lead to places receiving 40 to 50mm accumulated precipitation from the afternoon (2pm) into the evening. 

It said significant impacts are possible due to it being the first significant rainfall for the season.

“Therefore run-off is expected to be high, combined with possible blocked drainage systems. The midweek forecast indicates isolated showers and thundershowers over the central and northeastern parts of the country, with possible showers and rain along the south coast,” said Saws.

Providing a seasonal outlook for rain early this month for the remainder of spring and midsummer over Southern Africa, the weather service said it was not certain — the probabilities for above-normal rainfall which is usually expected during à La Nina event is low and a bit patchy.

The weather service predicted à La Nina event bringing hotter temperatures for the next few months but said the rain outlook is unclear.

Further, it said the El Nino Southern Oscillation (Enso) is in a neutral phase with a high likelihood of à La Nina event developing during Spring (September to November).

A weak La Nina event is expected in the 2024-25 summer season, Saws said. 

“The seasonal prediction can be generated to midsummer (December-January-February). Without strong Enso forcing, rainfall predictions from different seasonal prediction models show variation or no clear signal whether above-normal or below-normal rainfall is favoured over a particular area.”

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