Summary of significant satellite signatures involving thunderstorms

Severe weather warnings over the continental U.S. have traditionally been mainly based on radar data and spotter information. Very little input to field office forecasts has resulted from satellite imagery, because of the relatively late receipt of the data and lack of looping capability. But with the addition of SWIS (Satellite Weather Information System) to weather offices across the United States, real-time "nowcasting” of convective activity is now possible using satellite imagery. Satellite data contains a wealth of information! A detailed look by the trained forecaster can yield a three-dimensional picture from a "birds—eye" view of the mesoscale environment. Characteristics of individual cells can be identified, determining strength, stage of development, dissipation, and much more. In addition, features of the convective scale environment can be identified, defining areas for possible later thunderstorm formation, dissipation, or intensification. Satellite imagery can "fill in the gaps" left behind by conventional surface, upper air, and even radar data. It is an extremely powerful tool if used by trained field forecasters. The goal of this paper is to provide field personnel a short, complete list of the most significant characteristics of convection visible in satellite imagery. The list, plus a brief description of each feature, will alert forecasters of what to look for in a satellite picture, and what each signature means. This short technical attachment is the nucleus of a much larger, more comprehensive slide training program developed at the Louisville WSFO. Information included has been compiled from numerous reference articles and case studies. For brevity, examples have not been included, though they are available.