Small stock farmers in the Eastern Cape, hikers in mountainous areas urged to take precautions as widespread cold and wet weather approaches
A spell of very cold and rainy weather is expected to affect the Western, Northern and Eastern Cape from Thursday May 11 2023, extending into the weekend, according to the South African Weather service. The National Forecasting Centre’s report follows:
This rainy spell will be heralded by the arrival of a cold front over the south-western part of the Western Cape on Thursday morning. Daytime temperatures are expected to drop significantly over the southern half of the country, while a range of wintry weather can be anticipated, including widespread significant rainfall and snowfalls over mountainous terrain as well as marine gales and very rough seas over the southern oceanic areas.
Upper-air troughs as well as closely related cut-off lows are a familiar feature of weather over southern Africa and are associated with prolonged episodes of rainfall, often of an extreme nature. It is noteworthy that the extreme rainfall and flooding which affected KwaZulu-Natal (KZN) during April and May 2022 were associated with cut-off low weather systems on both occasions.
Firstly, a well-developed upper-air trough will start nearing the Western and Northern Cape from Thursday onwards, subsequently cutting off and establishing a cold core, characteristic of cut-off upper-air systems. Secondly, a particularly strong southern Atlantic high-pressure system is expected to extend a ridge eastward in the wake of the cold front, introducing pronounced and sustained onshore flow along the southern coastline of Western Cape as well as the Eastern Cape during the weekend. Moreover, the presence of coastal mountain ranges (such as the Outeniqua and Swartberg) will enhance vertical motion of air, thus enhancing the likelihood of heavy orographically-induced rainfall. It is therefore this combination (or juxtaposition) of surface and upper-air systems which is expected to raise the likelihood of significant, widespread and heavy rainfall, especially over the coastal mountain regions, leading to localised flooding.
Day-time temperatures for this week are expected to drop significantly from Friday into Saturday, where maximum temperatures may be below 10°C in places. Light snowfall is possible over the south-western mountains of the Western Cape as well as the southern high ground of Northern Cape on Friday afternoon into Saturday.
The sea state will also be affected with wave heights of 4.0 to 5.0 m between Alexander Bay and Plettenberg Bay from Friday into Saturday. Strong to near gale force south-easterly winds are expected north of Cape Point on Friday, while spreading along the south coast on Saturday. These strong winds, accompanied with significant wave heights, will result in very rough and choppy sea conditions.
Cloudy and cold to very cold weather will dominate the Northern and Western Cape from Friday onwards, spreading to include most of the Eastern Cape during the weekend. Widespread rain and showers will accompany this system, with the likelihood of heavy rain and localised flooding being of particular concern for the southern and south-eastern coastline and adjacent interior, as alluded to earlier.
Given the expectation of an extended spell of cold, wet weather as well as the possibility of snowfalls over mountainous parts of Western, Northern and Eastern Cape, farmers of small stock are advised to move animals to dry shelters at lower elevations. Moreover, only experienced, well-prepared hikers and climbers should venture into the mountains and hiking trails of Western and Eastern Cape this weekend. The risk of hypothermia in mountainous terrain, especially if lost, injured or ill-prepared could prove to be life-threatening.
Furthermore, the public are urged and encouraged to regularly follow weather forecasts on television, radio as well as social media platforms. Further weather-related media releases will be issued during this week. Updated information in this regard will regularly be available at www.weathersa.co.za as well as via the SA Weather Service Twitter account @SAWeatherServic
