Isolated thunderstorms predicted for Mbombela this afternoon
Residents are to note that a late-afternoon spring thunderstorm is possibly on the cards, according to the SAWS.
According to the SAWS, isolated thunderstorms are expected later this afternoon over the eastern areas of Mpumalanga.
🌞Morning satellite image for today, 20 September 2023. Currently, fine and warm conditions, with isolated thunderstorms expected later in the afternoon over the eastern areas of Mpumalanga. #WeatherUpdate #WeatherForecast #sabcnews #GAUTENG #MPUMALANAG #SABCWeather pic.twitter.com/SY5wp54IzO
— SA Weather Service (@SAWeatherServic) September 20, 2023
“It’s that time of the year when the weather patterns are in the extreme. There is a 30% change of isolated thunderstorms predicted for Mbombela on Wednesday. Residents must be cautious, as the storm can possibly be accompanied by hail, heavy rain and strong winds,” said the SAWS.
Listen: SAWS weather forecaster – Lehlohonolo Thobela:
Also read: General rules to consider when heavy storms threaten
Mpumalanga Today 's Weather overview: 20.9.2023 pic.twitter.com/NjDec9G0Bt
— SA Weather Service (@SAWeatherServic) September 20, 2023
Some storms wreaked havoc in various parts of North West and Gauteng on Tuesday night.
⛈First Spring thunderstorms over the eastern parts of SA. A lot of storms around GP this evening (19 Sept 2023). These storms are producing strong winds but not a lot of rain. pic.twitter.com/ux7I1HtvHG
— SA Weather Service (@SAWeatherServic) September 19, 2023
A resident of Tshwane, who preferred to stay anonymous, told Lowvelder that the maximum wind speed recorded in Sinoville was about 92kph.
“It was very scary. It was a huge storm with wind gusts I cant explain in words. As I drove to work this morning, I could see the damage caused by the winds. Shade nets from car dealerships where completely blown off, and in parts of Menlopark and Gezina, road signage boards were lying on the ground,” she said.
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All signs indicated that it was a squall or frontline storm.
What is a squall?
According to Jan Meintjies, weather expert and Facebook group administrator of Reënval Suid Afrika, frontline winds are synonymous with thunderstorm winds where there is no rotation, as in the case of a tornado.
“Straight line damage is a common cause of wind damage from a thunderstorm. They can reach over 100km/h and are caused by air drawn down by precipitation during a thunderstorm. When the air reaches the ground, it spreads outward over the surface of the land it encounters in a straight line. With other words, the worse the precipitation, the worse the wind,” said Meintjies.
However…
The SAWS confirmed it was a dry microburst characterised by widespread reports of strong, damaging surface winds as well as very modest amounts of rainfall.
What is microbursts?
“A microburst is a localised column of sinking air (also known as a downdraft) within a thunderstorm and is usually less than or equal to 4km in diameter. Microbursts can cause extensive damage upon reaching the Earth’s surface, and in some instances, can be life-threatening. In the case of a dry microburst, the precipitation evaporates aloft within the downdraft, causing the downdraft air to become colder and denser, thus accelerating the cold air towards the ground, under the influence of gravity. This phenomenon is typically associated with high cloud base thunderstorms, as was the case yesterday. This weather phenomenon has the capability of uprooting trees as well as lifting off buildings’ entire roofs, as indicated in the photos of the storm damage below,” said the SAWS in a statement.
