Gale force south-westerly winds are expected between Table Bay and Cape Agulhas and possible heavy rain over the south-western parts of Western Cape.
Extremely high fire danger conditions are also expected over the central, eastern and northern parts of the country, due to hot and dry conditions and strong interior winds ahead of the cold front. The upper-air trough associated with this cold front will result in possible thunderstorms over the central parts of the country.
On Friday, 20 September 2013, the cold front will move over the central interior and the Atlantic high pressure ridging behind it will bring more cold, wet and windy conditions over the Cape provinces.
Very cold conditions will dominate the Western and Northern Cape interior, with snowfalls expected over the south-western mountains and gale-force south-westerly winds spreading to the Eastern Cape coast.
The upper-air trough will intensify as it moves over the western parts of the country, enhancing thundershower development over most of the central, southern and eastern parts of the country as well as the north-eastern corner.
Cold to very cold conditions are expected to reach Gauteng, KwaZulu-Natal and Mpumalanga by late afternoon and evening of Friday, 20 September.
On Saturday, 21 September, the cold front will exit the country and the upper-air trough will be positioned over the central interior. The high pressure system will continue to feed cold air into most parts of the country, resulting in cold and windy weather conditions, but very cold on the high grounds.
Snow will is expected on the Eastern Cape high ground and Lesotho mountains. By Sunday, 22 September the weather will clear up as the system will be east of the country.
Temperature recovery will take place in most of the interior.
The South African Weather Service issued the following weather watches:
1. Very cold conditions are expected on the high ground of the Western Cape province and the interior of the Northern Cape on Thursday night, spreading into the Eastern Cape high ground and southern Free State, persisting until Saturday, 21 September.
2. Snowfall is expected over the mountains of the Western Cape and the southern high ground of the Northern Cape on Thursday night, spreading to the Eastern Cape high ground and Lesotho mountains on Friday, 22 September.
3. Heavy rain, with possible localised flooding, is expected on Thursday into Friday in areas in the Cape Metropole, Overberg and the southern parts of Cape winelands district of the Western Cape province.
4. Strong winds are expected on Thursday over the interior of the Western Cape, the southern interior of the Northern Cape, Eastern Cape interior, Free State and in places over North-West Province.
5. Gale force winds (65-74 Km/h) are expected between Table Bay and Cape Agulhas on Thursday, 19 September, and will spread eastwards along the south coast of the Eastern Cape Province on Friday.
The Cape Town City’s Disaster Risk Management Centre has analysed the weather watch and is preparing for the potential heavy rains in the Cape Peninsula that will extend over the weekend.
The situation will result in the already wet soil in low-lying areas being saturated, and the above normal river levels will make areas vulnerable to flooding.
There is also a risk of landslides, mudslides and rockfalls on the City’s mountainous areas, and particularly where there are steep slopes due to periodic heavy rains. Residents who live in these areas are advised to ensure that they take precautionary measures and to consult with their private insurance companies for appropriate cover for emergency repairs to be undertaken.
Mossel Bay 1 – 3 Day Weather Forecast Summary: Light rain (total 7mm), mostly falling on Fri afternoon. Warm (max 20°C on Thu afternoon, min 8°C on Fri night). Winds increasing (calm on Thu morning, strong winds from the WSW by Fri afternoon).
Sources:
1. NCEP
2. Cape Town Disaster Management
3. SAWS
4. Weather Forecast.com
