Research has shown the color used to represent threat information can influence perceived risk and how individuals respond to watches and warnings. However, there is no standardized color scheme for hazardous weather products across the weather enterprise. This study’s objective was to determine if color inconsistencies have an effect on a product’s intended risk perception utilizing two public surveys. Results suggest color inconsistencies when representing hazardous weather products have a detrimental effect on that product’s intended message. The first survey found people use color to help determine risk and rely on whether a filled or outlined polygon is displayed. The second survey found the term “warning” is perceived to have more risk than the term “watch” for all hazardous weather types tested. The results from both surveys suggest a national, uniform color scale based on risk should be implemented across all weather enterprise agencies.

M.Ing. / Globally, hazardous weather phenomena such as violent storms, oods, cyclones, tornadoes, snow and hail contribute to signi cant annual xed property damages, loss of movable property and loss of life. The majority of global natural disasters are related to hydro-meteorological events. Hazardous storms are destructive and pose a threat to life and property. Forecasting, monitoring and detecting hazardous storms are complex and demanding tasks, that are however essential. In this study automatic hazardous weather detection utilizing remotely sensed meteorological data has been investigated. Image processing techniques have been analyzed and applied to multispectral meteorological satellite image data obtained from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) instruments on-board the Meteosat Second Generation (MSG) geostationary meteorological satellites Meteosat-8 and Meteosat-9. The primary focus of this study is the detection of potentially hazardous hydrometeorological phenomena in South Africa. A methodology for detecting potentially hazardous storms over South Africa using meteorological satellite imagery from MSG/SEVIRI is presented. An index indicative of the hazardous potential of a storm is de ned to aid in the identi cation of a ected geographical areas and to quantify the destructive potential of the detected storm. The Hazardous Potential Index (HPI) is generated through the use of image processing techniques such as cloud masking, cloud tracking and an image-based analysis of the constituent elements of a severe convective storm. A retrospective review was performed with respect to 20 case studies of documented storms which had adversely a ected areas of South Africa. A red-green-blue (RGB) composite image analysis technique, that may be utilized in the identi cation of severe convective storms using SEVIRI image data, was also applied to these case studies.