24 January 2014

What Happened
This week it was Tsumeb’s turn to play host to stormy conditions as the eastern side of the town was pelted by a heavy downpour and accompanying storm wind. Afterwards light rain continued for most of the day as well a during the night, the next day, Tuesday, and during Wednesday. But 10 km away from the epicentre of these conditions, only minor falls were recorded.
This pattern is typical of the development of rainy conditions in this season so far. While overall conditions are much better than the same time last year, there is still an observable high pressure control in the upper layers, i.e. above 35,000 feet.
This presence inhibits convection, the second most important requirement for cloud formation, after moisture.
Looking at the unfolding synoptics since last week Friday, the descending air pattern that was stationary over Hardap and Karas, causing the excruciating heat of the previous week, has shifted eastward, now sitting more or less above central Botswana.