The South African Weather Service (SAWS) has warned of heavy rain to hit the eastern parts of South Africa on Tuesday.
The eastern half of the Eastern Cape and the southern parts of KwaZulu-Natal can expect heavy rainfall which could lead to localised flooding, SAWS warned.
Significant rain is already falling in Port St Johns which has seen 14mm so far.
"At the moment there is a subsurface high-pressure system that is just south of the country. It's pushing low level moisture into the southern parts," SAWS forecaster Bransby Bulo told News24.
SAWS predicted thundershowers for the eastern parts of the Eastern Cape and widespread showers over the southern parts of KwaZulu-Natal.
In the western half of the Free State, there will be widespread showers and thundershowers, but these will be more scattered toward the east of the province.
Bulo attributed the thundershowers to moist air flow from the north.
"Moist tropical air is streaming down from the north, coming from the central parts of Africa. The two systems converge and you can expect a lot of rain over these areas."
He added that SAWS officials have been in contact with provincial disaster management officials so that they can prepare for the wet weather and possible flooding.
"Our office in Port Elizabeth has been in contact with disaster management services," he said.
Bulo added that the wet weather was typical for this time of the year.
The rain should be good news for Eastern Cape dams, which were 50.8% full when measured on February 10, compared to 59% in 2019.
KwaZulu-Natal dams were 58.7% full, compared to 55.5% in 2019.