Understanding Weather – not predicting – 03 May 2013

What happened?
The strangle hold of the Atlantic high pressure cell in the upper air above 35000 feet has grown in spread as well as in depth.
A marked anti-cyclonic circulation was prevalent over most of southern Africa for most of the week. This created an area of somewhat lower pressure on the Kaoko coastline but the impact was mostly confined to the areas adjacent to the coast.
It also lead to a rare weather anomaly, at least for this time of the year. It created a diabatic effect over a large part of the central plateau and the north eastern third of the country.
The results was unseasonally warm afternoons as evidence by the very warm weather at the beginning of the week.
The presence of a strong high pressure cell to the south west, however, dispelled this effect by night, hence the relatively cool night temperatures.