Model data continues with the depiction of a weekend of
Weather around the country has been moderately interesting of late, Durban experienced a cool period a week or two ago which saw temperatures drop to around 20’C, though since then the KZN province has been back to the summer ‘norm’ with thundershowers and highs in the upper 20s to low 30s. The northern parts of the country have been experiencing more typical weather patterns with warm to hot conditions and thundershowers present, there have also been some large thunderstorms noticed on radar over the past couple of weeks, but no real reports of anything too severe of late.
The Western Cape on the other hand has been experiencing weather conditions which are quite bizarre for this time of the year. Temperatures have been around the low to mid 20’s mark for the most part recently, with just a few days where temperatures were able to make a dart for the 30s, though typically not getting there. Instead of the south easterly flow which is brought on by a stable high pressure ridge, this ridge hasn’t been where it typically is at this time of the year, instead causing more southerly flow which has caused cooler temperatures. It is nothing too unusual to have a setup that is a bit late or a bit early, conditions are currently much like early November but I’m sure it’s only a matter of time before the ridge establishes itself and the Cape can feel real summer again.
The main talking point is somewhat related to the above paragraph and eyes are currently on a rather intense cold front which is approaching the Western Cape at the moment and it’s impact will be felt mostly today Tuesday and tomorrow Wednesday. Showers are likely to begin into this evening with the bulk of the rain falling between the early hours of tomorrow morning and tomorrow afternoon. Summer is usually void of deep low pressure fronts, but this front has an estimated central pressure of around 1000mb as it passes just south of Cape Town tomorrow. The effects are going to be a dramatic drop in temperatures, rainfall and possible strong north westerly winds.
This front is likely to bring rainy weather to areas of the Eastern Cape and Kwazulu Natal over the coming days as it passes on east.
Looking ahead at the long term GFS, it seems possible that we may go through the whole of December without an established summer weather pattern. Throughout the forecast period there is very little ridging in places and several weak cold fronts come quite close to making landfall, from the looks of it the next 14 days will possibly just be mild (with some exceptions of course). But can’t see any signs of a heat-wave just yet.
The question as to why the pattern is different is difficult for me personally to say, I am aware that we are in a La Nina cycle at the moment, and there are ties to La Nina bringing excessive rainfall to the northern areas of South Africa during summer, this would mean an increase in the amount of troughs and instability. But the studies have shown far less impact on the central and western areas of the country. I suppose it is possible though that an increase in the amount of low pressure troughs can have an impact on how the ridge sets itself up over the central and western parts.