28 May 2009 Update The latest GFS model run (18z,
It’s only been a few days since the recent cut-off low brought snow to several provinces, but already we can look to the next potential snow event which seems to be possible later this week.
There is currently a weak upper trough present over Namibia extending down into the Northern Cape. The GFS model suggests that this upper trough may close off into a cut-off low, but the model has been flip-flopping a bit and it’s possible that it may remain an open trough as it moves eastward over the course of the week. Never the less, it’s looking likely that the Southern Drakensberg will experience some good snowfall from Thursday through into this week. While most of the snow will fall within the Lesotho borders, there’s also a chance for snowfall in north-eastern part of the Eastern Cape. As far as freezing levels are concerned, they have been fluctuating in the recent forecasts and the 00z GFS on Monday is less promising than the 18z GFS from Sunday night. Because of this uncertainty, it’s worth continuing to monitor the situation as it approaches for clearer outlook.
With the current forecast of timing, it appears that majority of snow will fall Thursday evening into early on Friday morning and then begin to clear a bit later into the day. Snowfall totals could be in excess of 10cm in areas. Given that the weather system is quite fast moving, it would appear to be a great setup for snow chasers – with the likelihood of snow being present well into the weekend with clear skies and modest temperatures forecast.
Please note that this system is still 3 days out and specifics of the timing or snow amounts may change.
Update #1 – 9 June 2015
Today’s update shows far less favourabe conditions for heavy snowfalls that were suggested by models earlier in the week. While it still looks likely that Lesotho will experience some snow, both freezing levels and associated moisture have decreased. The system will also be moving much further north than originally forecasted, and shifting the focus from the entirety of Lesotho and into the Eastern Cape, towards the northern parts of Lesotho. While freezing levels are of concern, the primary shift in the potential seems to be related to the lack of moisture – and so at this point things could still change with any chances of forecasted moisture.
Update #2 – 11 June 2015
The cutoff-low has eventually materialised, though the models have fluctuated condiserably, as discussed in the previous update. This morning (Thurs 11th) there is a considerable amount of convection over the Free State, which is a good sign for snow later. A little more detail is available in a short article in the discussion forum: Cutoff-low and Lesotho snow 11 Jun 2015