What happened
Namibian wintertime has much to recommend in the way of sunshine hours, moderate daytime temperatures and “nice” holiday weather when compared to Temperate Climate statistics.
Generally, this “nice” pattern has been present for the past few days.
The coastal weather saw the decline of East wind conditions.

Inland, daytime temperatures have exceeded 20oC with such warmer temperatures persisting for some 6 hours each day. Nighttime temperatures have risen from the frosty levels into the lower single figure range. The difference can be felt as a move from very cold and chilly to cold but bearable for the human skin.
So it would look like return to “normal” winter weather; but not quite.
The upper air, that means the levels between some 30000 to 45000 feet, finds itself cut across by jet stream flows. These indicate a sharp drop in the Tropopause, the dividing line between the Troposphere (where weather happens) and the Stratosphere which lies above the weather as we understand it here on the surface. Although, technically, there are weather occurrences in the stratospheric levels, these have much to do with Solar variation rather than heat and cold devolving from air flows at the surface and immediately above it. Jet stream presence indicates that the normal upper air controls are displaced, allowing these disturbances “room to move” or are thrust aside by influences enabling the jet-stream flows to make their mark. The various patterns of Cirrus cloud, pure ice particles, of the past few days have provided some visible sign of the upper disturbance.
The usual way of looking at weather and recording what there is to be seen is done by the personal observation of thousands of weather observers, world-wide. These reports are dispatched on an hourly, 3-hourly, 6-hourly or 24-hourly basis (depending on the status of the observation station) to the regional centre and thence internationally. For the past generation, these surface observations have been supplements by observations from outer space: Satellite images. These are used to provide indications of weather, in particular, from areas where surface observations are scarce or non-existent. As one can imagine, this weather observation tool is of considerable use to the forecaster and weather users in aviation and maritime travel, and in agriculture.