Today's model runs (GFS and NOGAPS up to 12Z on Sun 23rd) continue to evolve and converge, but still not enough to give specific predictions for the cutoff-low on Fri 28th and Sat 29th. The chance of heavy rain over Cape Town seems less, since the combination of upper instability and surface moisture seems unlikely to occur.
To give some idea of the overall size and intensity of the upper trough driving this event, it is worth looking at the 500 hPa level temperatures: www.cpc.ncep.noaa.gov/products/african_d...safrica/temp500.html
This custom GFS chart at 18Z on Fri 28th shows a very large disturbance in the upper air, about 15C below the seasonal average.
Compiled by Gordon Richardson - Stormchasing SA
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