The Scientific Basics of Lightning

Abstract

Lightning is a source of amazement and concern for virtually everyone around the world. What is it, how does it happen, why does it have such seemingly strange and random effects, and how can it act so weirdly? As a result, stories about how lightning forms and what should be done to avoid it have been the source of speculation and embellishment everywhere through the ages. There is an established scientific system about how to look at lightning, its formation, detection, and how to classify it. This chapter will describe how lightning forms, and the categories of cumulus clouds that contain lightning are followed through the cumulus growth cycle. The chapter continues with a detailed description of accepted and commonly-used lightning terminology, such as negative and positive cloud-to-ground flashes and strokes, in-cloud lightning, and heat lightning. Since the mixture of meteorological factors affecting Arizona lightning does not occur in the same blend anywhere else, a description is made of the factors that result in lightning during the monsoon season from July through September. These factors are daytime turbulence from heating, major elevation changes, mesoscale convective systems, inverted troughs, as well as hurricanes and tropical storms. Outside of the monsoon season, large-scale traveling meteorological systems can result in lightning in the state. In addition, lightning occurrence is associated with rainfall in sometimes complex processes.