Synopsis: This chapter addresses ways in which convective storms affect and are affected by external processes. Perhaps the most familiar of such interactions involve convective-storm “remnants” like outflow boundaries and mesoscale-convective vortices. Chapter 9also explores convective influences on the synoptic-scale dynamics, especially through the diabatic heating due to the convective storms. Finally, the roles of mesoscale-convective processes over longer time scales are considered. This includes feedbacks involving the land surface type, and global radiative forcing, and the formation of precipitating convective clouds.

Introduction

Taken in order of increasing length scale, time scale, and complexity across these scales, some of the ways in which convective storms affect and are affected by processes external to the storms are explored in this chapter. Frequently implicated in such interactions on the mesoscale are storm “remnants” introduced in Chapters 6 and 8, namely, outflow boundaries and mesoscale convective vortices (MCVs). Both are convectively generated, persist long after the demise of the generating storms, and thereafter help initiate new convective storms. The diabatic heating due to convective storms influences the synoptic-scale dynamics, particularly in terms of surface cyclone development and intensification. This interaction is two-way, because an effect of a deepening cyclone is to enhance transports of heat and water vapor. Locally, this helps to sustain ongoing, and support subsequent, convective activity.