This post will be a mix of meteorological discussions about
As predicted several days ago, the past few days have seen a variety of severe weather scenarios, all due to a cut-off low pressure system which developed early in the week in Namibia. The cut-off low’s first significant effects were felt on Tuesday 7th June 2011 when snowfall began in Namibia, a rare but not unheard of occurance. The snow in Namibia accumulated enough to last several hours and attracted much attention from South Africans, Namibian locals and those around the world. Naturally when one thinks of Namibia, you picture deserts and dust, well this time the freezing level allowed for the grounds to be coated in a thin layer of snow. An image of a zebra grazing in the snow certainly captured the environment. An interesting discussion was sparked in the discussion forum about the nature of these snow flurries and the possibility that it was a thundersnow event.
The cut-off low then moved in an ESE direction, where it was responsible for setting off thunderstorms in the central parts. Severe thunderstorm warnings were issued, with conditions looking ripe for severe cell development. In the end there were several large thunderstorms, but I haven’t heard of any reports of large hail which is usually associated with severe thunderstorms.
The cut-off lows main threat was always flooding and by Wednesday it was dumping extremely heavy rains over many of the countries provinces, most particularly the Free-State and the Eastern Cape, areas as far south as Mossel Bay received 24 hour rain figures in excess of 150mm! Earlier in the year Mossel Bay had been under a severe drought, but over the past couple months heavy rainfall has seen the dam levels in the area skyrocket.
The highest rainfall totals for the period from Wednesday the 8 June 2011 to Thursday 9 June 2011 were: Mossel Bay (Rooiblom ARS) 159mm, Ladismith (WC) 103mm, Uitenhage (EC) 87mm, George (W/O) 76mm, Patensie (EC) 63mm, Port Alfred (EC) 56mm. There were several rescue efforts in areas where flooding was present.
The rainfall figures diminished further to the south, though Grabouw in the Western Cape managed to get some decent rainfall. Cape Town, which while spared from the rain – suffered wind damage associated with the cut-off low. Reports were that a sign at the Cape Town Hospital had been damaged by strong gusts.
The KZN coast seems to have been spared from the original forecasts of rain. Estimates earlier in the week suggested as much as 80mm forecast for Friday the 10th June 2011, though this is now standing at a forecast 12mm.
Snowfalls were experienced in Soweto overnight on Thursday, though didn’t last long as temperatures remained borderline. Snowfalls are expected tonight Thursday and into Friday along the Drakensburg. The system has still not passed, and further rainfall is expected today, though not to the extent of yesterdays rainfall.