Earth is struck by lightning more than a half billion times each year, with several times that number of discharges remaining within the clouds. Worldwide, lightning deaths, injuries and economic losses are comparable to or exceed the major “severe weather phenomena” that tend to garner greater public notice, and often higher research prominence. Though Benjamin Franklin’s pioneering research on the “electrical fluid” lead to practical basic lightning protection technologies more than two centuries ago, progress in understanding, measuring, predicting and warning against the lightning hazard has, until recently, been slow. Measurement technologies have slowly evolved since the first known lightning photographs in the 1880s. Lightning flash counters in the mid-20th century and coordinated airport observations of lightning and thunder for aviation were followed by increasingly advanced film, video and RF techniques for investigating the lightning discharge. But not until modern electronics allowed for the design, deployment and operation of regional CG lightning detection systems (LDS), did the natural variability of lightning characteristics begin to be understood, highlighting how little we know about the fundamental physical processes which control lightning. Why the marked land/ocean contrasts in lightning? Why do +CG flashes favor certain convective regimes and geographic regions? The motivation behind the proposed Houston Environmental Aerosol Thunderstorm (HEAT) Project will probe the extent and processes by which large cities significantly increase the lightning hazard to its population and vulnerable infrastructure. What can lightning tell about tropical storm intensification? Could atmospheric electrical activity serve as an indicator in large scale global climate change?

The advent of 3-D VHF lightning mapping systems combined with LDS networks for the first time quantifies “total lightning”. New measures, such as charge moment change, derived from ELF remote sensing, provide a new metric of the CG stroke. Such data should significantly enhance severe storm identification and warnings plus assist in aviation operations. Though in its early stages, assimilation of lightning data into forecast models shows promise. The quantification of boundary layer lightning NOx inputs may influence regional photochemical ozone modeling and forecasting. New discoveries of upward lightning from thunderstorm tops, plus lightning-induced stratospheric sprites, jets and trolls must be factored into the design and operation of proposed new, stratospheric high altitude airships and high speed civil transports. The use of real-time time lightning data to warn the public of impending hazards, secure vulnerable facilities, and diagnose other severe weather threats is rapidly emerging. Climatological uses of lightning data range from forensic/insurance claim verification, accident reconstruction and the design and siting of lightning-sensitive industrial and energy facilities. Research measurements from space (OTD, TRMM, FORTE, ROCSAT II) hopefully will pave the way for long-overdue operational geosynchronous global lightning monitoring.