The appearance of an equatorial wave
, the Inter Tropical Convergence Zone in its most active form, from late December through to this week, situated between 15 and 20oS, ensured a consistent moist air presence close to our northern regions.
The "delayed oscillator" mechanism emphasizes eastward-propagating equatorial wave
processes,(*) westward-propagating off-equatorial signals, and their asymmetric reflections at eastern and western boundaries respectively.
An equatorial wave
drifts along the northern border while a cold front sweeps across far south of the Cape.
The equatorial wave
weakens though as it drifts further west, but advected moist air penetrates into central Namibia.
Meanwhile a further Equatorial wave
develops in a similar time range.