Media Release: Very cold wet and windy weather to persist over the Cape provinces in the week ahead.

For immediate release
13 June 2023

Very cold wet and windy weather to persist over the Cape provinces in the week ahead.

A well-developed, fast-moving cold front arrives over the Western Cape tomorrow, introducing very cold, rainy weather to all three of the Cape provinces. In addition, strong, gusty westerly winds over the interior of Western and Western Cape are expected to accompany the passage of the cold front. Given the dramatic drop in temperature, combined with persistent wet and windy conditions in the days ahead, small stock farmers are strongly encouraged to take mitigative action at an early stage to prevent stock losses due to exposure.

Moreover, the arrival of the cold frontal system tomorrow will be the first in a succession of such systems, expected to pass through the Cape provinces in the week ahead, on an almost daily basis.

Cold, windy conditions with occasional showers will therefore be a persistent feature of the weather over the southern half of the country, continuing until well after the long weekend.

The latest output from Numeric Weather Prediction (NWP) models, in particular the Unified Model (UM) (refer Figure 1 below) suggest that heavy rainfall may occur over parts of Western Cape tomorrow Wednesday 14 June, persisting on Thursday 15 June.

Typically, the presence of higher topography and especially mountainous areas tends to markedly enhance local rainfall through orographic uplift. The western, or windward, side of hills and mountains of the Western and Northern Cape can therefore expect to receive upwards of 100 mm of rainfall on Wednesday, with further significant rainfall of the order of 50 mm or more, persisting on Thursday. This NWP guidance has prompted SAWS to issue a Level 6 Orange warning for disruptive rainfall, expected to affect particularly the Cape Town CBD and Metropole as well as the Winelands area (see additional details below).

Strong, gusty winds (possibly gusting beyond gale-force) are anticipated over much of the interior of Western Cape and Eastern Cape tomorrow and Thursday. High-sided vehicles travelling along major roads and highways could be at risk of being severely buffeted by crosswinds. Drivers of such vehicles are encouraged to reduce speed and to exercise due caution in this regard.

Strong to gale force winds are expected to occur along the Western Cape coast between Saldanha Bay and Plettenberg Bay on Wednesday and Thursday, combined with very rough sea conditions of 4,5 to 5,0m, which will lead to difficulty in navigation at sea and may cause problems for small marine vessels.

The following Impact-Based weather warnings have been issued by the South African Weather Service (SAWS):

A Yellow Level 2 Warning for disruptive rain leading to localised flooding of roads and settlements can be expected over the southern West coast, south-eastern Cape Winelands and western Overberg districts on Wednesday and Thursday (14-15/06/2023). Impacts may include difficult driving conditions and minor motor vehicle accidents due to slippery roads.

An Orange Level 6 Warning for disruptive rain leading to major disruption of traffic flow can be expected over the City of Cape Town and most parts of Cape Winelands on Wednesday and Thursday (14-15/06/2023). Impacts may include flooding of roads and settlements and damage to property and infrastructure.

Furthermore, members of the public are encouraged to regularly follow weather forecasts on television, radio as well as social media platforms. Updated information in this regard will regularly be available at www.weathersa.co.za as well as via the SA Weather Service Twitter account @SAWeatherService.

Compiled by Kevin Rae and Stella Nake (CT and PE forecaster input)
Edited by Wayne Venter

Approved by Tshepho Ngobeni, Senior Manager DRR
For technical and weather enquiries:
National Forecasting Centre: Tel: 012 367 6041

Report weather related incidents to the Garden Route District Disaster Management Centre at 044 805 5071.

ENDS