When the dominant weather patterns are to be found in the temperate weather zone, that is from about 35o South towards the south pole and the season is other than summer, the whole weather pattern is active, well inclined to changeability and moving with considerable speed. Tropical patterns on the other hand, can be active but changes happen slower and systems move even slower. Tropical revolving storms, i.e. hurricanes, typhoons and cyclones proceed at rates slower than10 knots, despite their internal storm winds.

A week ago, the focus lay on an approaching anticyclone which had budded off from the Polar zones south of the Falklands. With a ridge still extending into Antarctica and swirling air pushing a major cold front, the given prospect was for a cold air invasion extending as far north as our latitudes. Activity was on centre stage and as can happen, the swirling air undercut sections of the cold front even more conspicuously than the normal undercutting process and wave vortices developed, two of them, on the cold front. This localized activity slows up the cold front advance, so the anticyclone pushing the overall system slides round the two secondary vortices and pushes eastwards. The expected northward cold air push is thwarted. Usually when this weather development begins, its growth and applied effect is in place within a few hours. Under such conditions a weather map can change considerably from the one six-hour analysis to the next.
The net result was that our weather continued its balmy drift through these late autumn days.
The brief invasion of moist air prior to the cold front and its upper air trough brought some showers. The reported values are generally minimal but some reports noted falls of as much as 70mm: a record value for May! This ready ability to advect semi-tropical (if not true tropical, Congo, air) is a happily positive state. One cannot but hope that this ability will remain, at least in the weather wings if not on stage, as a more reliable feature of our weather patterns. The underlying cause can be attributed to an effect of global warming thus enabling the southward advance of moist air, even this late in the season.
What's coming
An upper air anticyclone dominates southern Africa. On the northwest side of this system, we lie in the warmest quadrant. Berg wind conditions (oosweer) prevails at the coast causing very warm temperatures throughout the weekend.
The southern ocean's synoptic map shows two semi-polar anticyclones present. The outlook again is for an active cold front and well-defined upper air trough to approach by Monday. This system will be drawing in semi-tropical air from mid-Angola. Alto-cumulus development is expected and thundery weather is likely within this pre-frontal cloud band. The expected shower area covers roughly the southern half of the country. Cloud should be developing in the course of Sunday and shower clouds building during Monday. The clearance (moving away eastward) occurs during Tuesday. Although next week is distant as far as weather outlooks are concerned, there is the anticipation that a colder burst of air invades the south, probably as far north as the central parts, during Tuesday night and into Wednesday. Because the driving anticyclone is a cold (polar in origin) anticyclone, the rapidity of its movement eastward tends to restrict the northerly thrust of its cold air circulation. The northern parts should remain warm. Windy conditions are to be expected.