The evolution of coastal lows along the south coast of South Africa
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Date
2005
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Abstract
Coastal lows occur frequently along the South African coast. Coastal low passage along the coast of southernmost Africa is signaled by a marked change in both wind direction and speed. Occasionally, a dramatic and rapid increase in wind speed takes place, which may cause damage to property and is potentially hazardous to aviation and shipping. Current global scale numerical weather prediction models do not forecast the intensity of these mesoscale systems well. A study of the coastal low is made with the aim of improving knowledge about the coastal low in general, and of strong coastal lows in particular, in order to improve the ability to predict the strong to gale force southwesterly winds associated with the more intense coastal lows. An average climatic profile of the coastal low is established in order to study the basic nature and evolution of the coastal low. This profile is compared against a similar profile of strong cases in order to locate mesoscale and synoptic scale elements that distinguish between normal and strong coastal lows. Links between intense coastal lows, and higher than normal pre-coastal low temperatures at surface and in the lower levels of the atmosphere over the southern parts of the country, are examined. The upper level northwesterly winds, associated with the upper troughs that follow closely behind the coastal lows, are a contributing cause in the development of stronger coastal lows on the south coast.
Description
Thesis submitted in fulfillment of the requirements for the Master of Science degree in the Department of Geography and Environmental Sciences in the Faculty of Science at the University of Zululand, South Africa, 2005.
Keywords
Mesometeorology--South Africa--Port Elizabeth, Winds--Speed--South Africa--Port Elizabeth, Weather forecasting--South Africa--Port Elizabeth