Cloud and Weather Symbols in the Historic Language of Weather Map Plotters

This talk chronicles the origin of the cloud and weather symbols celebrated on the AMS ties, scarves, and umbrellas. These symbols derive from the need to show conditions at weather stations on hand-plotted weather maps. Such weather mapping began in the 19^th century when telegraph began sending simultaneous observations of conditions at the surface of the earth to weather stations around the world. Indicating the complexity of the clouds and weather seen at a site needed a common naming system and simple symbols that were independent of language, since telegraph signals crossed international borders. Symbols of clouds needed to be related to pictures, and in the beginning only artwork could be used to illustrate types of clouds. But soon painstaking art renderings were replaced by photography—first black and white, then color. Nineteenth century meteorologists developed symbols for various cloud types in the form of simple lines and curves suggestive of the pictures. In contrast, weather symbols (for rain, snow, fog, hail, etc.) were drawn largely from typeface elements used in printing. These simple symbols suggestive of complex weather and clouds were used by skilled map plotters to transfer telegraph and Teletype codes to visually meaningful hand-produced maps. The skill of manual weather map plotting reached an apex in the 1940s-1960s. With advances in digital and satellite technology and automation of surface weather observations, the symbols and traditional mapping have been disappearing from daily use.