This report provides details of the design of a 24-hour weather prediction system for snow and ice control operations in road maintenance. The system accounts for detailed terrain effects on weather. Output is provided either in terms of weather maps at 3-hour intervals for meteorological users, or in terms of easy to read icons indicating rain, snow, temperature and wind conditions, laid on top of terrain and road network displays. These icons can be shown as time-lapsed sequences. Graphs of forecasts at specific locations can be manipulated by the user through simple mouse point-and-click actions, thus allowing forecast updates based upon local observations. The system has been tested extensively during the winter of 1991/92 and has performed excellently, providing details that go beyond those issued by the National Weather Service.