Triple-Doppler measurements are presented for a hailstorm of moderate intensity that occurred over the High plains of northeastern Colorado, and an airflow model is synthesized. The storm had a number of persistent features similar to previous descriptions of supercells. However, its evolution is shown to be intermediate in a certain sense between classical multicell and supercell models. A new model based on the Doppler observations, termed "weak evolution," emphasizes gradual changes in the structure of a long-lived updraft. The new airflow model explains the periodic echo intensifications noted for this storm, and seems to apply well to other storms discussed in the literature.

[This publication is referenced in the "Synthesis of knowledge of extreme fire behavior: volume I for fire managers" (Werth et al 2011).]