Durban – The SA Weather Services has warned that the current heatwave, bringing scorching temperatures over Gauteng, the North West, northern Free State, and in places in Limpopo and Mpumalanga, is set to last until Friday.
SAWS said extremely hot and dry conditions have been reported in various provinces, reaching into the high 30s.
“A heatwave is declared when the maximum temperature at a particular station reaches or exceeds the average minimum temperature for the hottest month for three consecutive days," explained the forecaster.
SAWS anticipates the current heatwave to last until Friday.
“Heatwave conditions are expected to continue over Gauteng, eastern parts of North-West, the eastern highveld of Mpumalanga as well as the south-western bushveld of Limpopo,” it said.
What is a heatwave?
A spell of at least three days or longer of very hot, dry conditions.
“While this term is commonly used worldwide, the meteorological agency for each country will typically customise their definition of a heatwave, to suit local conditions,” SAWS said.
What weather systems are contributing to the current heatwave?
A spell of dry, cloud-free weather over the past few days has allowed maximum levels of sunshine (insolation) to arrive over the interior of the country, with temperatures becoming incrementally higher every day. In addition, a very large upper-air high pressure system, (or anticyclone) has dominated the weather pattern over the southern African subcontinent in the past week, extending over much of Namibia, Botswana and the northern half of South Africa.
SAWS said apart from this feature blocking the arrival of tropically sourced moisture and thus delaying the onset of our summer rains, upper-air highs are well-known to be associated with large-scale air stability and sinking air masses.
“Such systems inhibit thunderstorm development, but perhaps more importantly in this case, the sinking air heats up quite dramatically,” it added.
What precautions should I take during a heatwave?
SAWS urges residents to stay hydrated by drinking water regularly.
“It is also best to avoid over-exertion when exercising, sport or leisure activities. In particular, infants and small children should be regularly supplied with fluids, as dehydration can set in very quickly. Similarly, the aged and infirm should also take great care during heatwaves, so as not to over-exert themselves,” SAWS said.
Those out in the sun are advised to wear hats and sunglasses to protect their eyes. SAWS also advised people to wear sunblock and where possible stay indoors between 11am and 3pm.
IOL