Gordon Richardson had the following to say in the forums
All eyes are currently on a frontal system that is expected to impact the Western Cape this coming weekend, between the 1st and 3rd of June 2013. Thus far, this season has been mild and quiet with very little strong frontal activity and ultimately very little rain, at least for the western parts, making this approach cold front the first real storm of the year. The past week has seen weather deteriorate quickly from the recent temperatures in the low to mid 20s. From the looks of it, it seems that winter is going to arrive with a bang though…
The cold front with an associated upper trough is currently to the far south-west of South Africa, though is already visible on satellite imagery. This system will begin to deepen as we approach the weekend, with a surface low pressure system developing and then deepening on Friday and Saturday, this surface low, associated with the cold front will then move north eastwards towards South Africa, before then moving to the south west, all the meanwhile remaining off shore by some distance.
The focus with this system is widespread, due to the surface low pressure that is going to form, and deepen to what models are suggesting will be between 991 and 996hpa – we can expect strong to gale force winds around the Cape from Saturday through until Monday. Typically an SLP of 996hpa isn’t that impressive with cold fronts, but due to the proximity of the storm pressures around Cape Town may drop to around 1002hpa during the peak. The wind currently looks likely to peak on Sunday.
We will also sea very high swells, with seas of 6 meters or more possible around the coast. Warnings will likely go out today from the South African Weather Service.
Heavy Rain is also a possibility with this system, the GFS has been forecasting between 70 and 120mm for the weekend as a combined total, with occasional 6 hour figures being as high as 30mm.
Snow is still seeming very likely with this approaching storm and snow-forecast.com is showing very impressive snow totals around the South Western Cape mountains, with the Ceres area looking as though it may get a good deal. Snow is also possible in parts of the higher grounds of the Northern Cape, Sutherland being quite likely to receive.
Due to the positioning of the front and the movement, the storm is likely to be felt most in the Western Cape, though it will also bring bitterly cold temperatures to other parts of the country in its wake.
Discussions on this system are ongoing in the forum: Cape Town Storm 1-3 June 2013