Most Geographic Information System (GIS) users do not realize that their GIS is also a sophisticated weather processing system (WPS). The ESRI ArcView GIS is competitive with several state-of-the-art WPS after reconfiguration for "look and feel" and some software additions. Important changes include weather data transformation to "GIS negotiable" formats (especially shapefiles), the acquisition of satellite images in standard projections, and modifications to support scene animation. GIS provides tremendous capabilities to analyze, transform, and visualize meteorological data. Existing modeling and analysis software are rapidly assimilated as extensions using data translators, and these extensions can be modified over time to work directly with GIS negotiable formats