Rainfall season 2008 may be considered dead, but it certainly does not want to lie down!
Friday's departing anticyclone advected moist into the far northeast: 10.5mm at Rundu, 18.5 at Mahango Lodge and 24mm at Katima, just to show what a small inflow can produce.
A week ago an intense vortex formed above the southwest coastal areas with the air-flow disturbance reaching a considerable altitude. In this case, the disturbance extended above 45000 feet. The regular top of the surface weather atmosphere, the troposphere, is somewhere between 52000 and at highest around 58000 feet. That divide which tops these levels is called the Tropopause. Above that level, the Stratosphere lives. So from above 45000 to the Tropopause during that weather pattern was very slender.

The actual system fell in the “cut-off low” category. Its ability to draw in moist air, in any depth, from the north was limited by the lingering anticyclonic flow on its northeastern side. It was to become more active east of Namibia. But some activity there was, 8mm at Warmbad, but very little compared to what such a vortex can produce.
However, its presence broke the anticyclonic grip and more “weather” was to follow.
As the vortex area departed, cooler air flowed in. Clear skies brought pre-dawn frost patches. Localised frost was noted in several places across the country.
But the weather patterns were now mobile and by Tuesday the north-to-south flow brought in a moist layer. Some cloud indicated this arrival.
Wednesday evening saw even more promising cloud development. Being air with a fair amount of tropical origin, the ability for overnight persistence and development never fails. By Thursday early morning isolated cumulo-nimbus clouds were there to be seen and provide light showers as far west as the coast where both Swakopmund and Walvis Bay measured rain. On the eastern side the system extended into Botswana.
This autumn activity was more reminiscent of summer weather while winter patterns were making their presence felt at the Cape and across the south of South Africa.
During the change-of-season this display can be expected but somehow there is the feel that the current display has roots ensconced in global climate change.
The La Nina in the Pacific seems to be waning, but ocean temperatures have cooled along Ecuador's coast. Also of interest are the two off-shore anticyclones around 60oS either side of South America: their impact is unclear, but a source of very cold air is found further north that one would expect.
What's coming
The present weather pattern is carried off eastward during this Friday, but the change may not be so obvious across the northern half until, at least, the weekend.
Succeeding frontal systems follow, but a major arrival seems booked for Sunday to Monday. A cold air invasion should reach our south, perhaps into the central parts. An effect of one of the Antarctic anticyclones.
The prospect of a frosty morning in the south is probable. But it must be re-emphasized, the risk of overnight frost remains for many more weeks ahead, even to September.