12. Mesoscale Convective Complexes: Vast Blue Light Shows
Large, ordered thunderstorm systems called mesoscale convective complexes (MCCs) can create broad displays of blue lightning. Usually forming in the warm season in the mid-latitudes, these storm systems could span regions more than 100,000 square kilometres. MCCs’ great scope and length provide perfect environment for blue lightning to be produced. Many times, as these systems change, they produce a sizable, cold cloud barrier high above. Comprising mostly of ice crystals, the top parts of these clouds offer a perfect forum for charge separation and lightning generation. At these high altitudes, the dry air lets the blue wavelengths of lightning travel enormous distances free from major scattering. Ground-based observers might see a vast canopy of blue flashes lighting the night sky, occasionally visible hundreds of miles distant. By use of the presence and dispersion of blue lightning, meteorologists investigating MCCs indicate the structural and intensity of the system, therefore enhancing forecasts and knowledge of these large-scale storm complexes.