Some Mesoscale Aspects of the 6 June 1990 Limon, Colorado, Tornado Case

Abstract

During the late afternoon and early evening of 6 June 1990, a series of severe thunderstorms produced nine tornadoes and numerous incidents of large hail on the High Plains of eastern Colorado. While the morning synoptic data clearly indicated a severe threat over the entire eastern half of the state, the severe activity that did occur was much more localized. Significant events were confined to a relatively small geographical region east and southeast of Denver, Colorado, including the small town of Limon some 70 miles to its southeast. Satellite, radar, surface, and upper-air data are combined in this paper to study some of the mesoscale aspects of the severe storm environment. Results show that thunderstorm outflow from a large mesoscale convective system in Kansas and Nebraska played a crucial role in focusing the severe activity in eastern Colorado. Also, the evolution of convective development during the early part of the day suggested the presence of a sharp moisture gradient along the Front Range of the Rocky Mountains, which further helped to localize the outbreak. Finally, interactions between individual storms appear to have been critical to severe storm evolution.