The central region of India was battered by prolonged, widespread and severe hailstorm events during the period of 15 February 2014 to 15 March 2014. The events were unprecedented not only in terms of time of occurrence, duration and frequency of hailstorms but also size of hailstones. In the present study, we have proposed a hypothesis which governs the mechanism for the development of severe hailstorms based on atmospheric instability, cloud microphysics and its feedback to large scale dynamics. The steep temperature lapse rate owing to warm (i.e. moist) south easterlies in the lower troposphere and cold (i.e. dry) westerlies in upper troposphere as a result of anomalous southward penetration of mid-latitude westerlies in the form of westerly trough fostered convective instability build up. The updraft associated with convectively unstable atmosphere invigorated growth of ice crystals by rapid collection of supercooled water droplets. This ultimately led to formation of graupel/hailstones through the microphysical mechanisms (e.g., riming process). The hypothesis is further tested with high resolution numerical model. The experiment pinpoints that mixed-phase hydrometeors were predominant in mid and upper troposphere and had bearing on the release of latent heat, further stronger the deep convective clouds (i.e., instability). Time evolution of cloud microphysical processes indicate dominant presence of graupel/hail which is consistent with formation of rain water, cloud ice and snow. The results underpin the interplay between large scale dynamical and cloud microphysical processes in the formation of anomalously widespread and persistent severe hailstorm events.

印度中部地区在2014年2月15日至2014年3月15日期间遭受了长期，广泛和严重的冰雹事件的打击。这些事件不仅在发生时间，冰雹的发生时间和频率方面，而且在冰雹的大小方面都是前所未有的。在本研究中，我们提出了一个假设，该假设基于大气不稳定性，云微观物理学及其对大规模动力学的反馈，控制着严重冰雹的发展机制。对流层低层南风东风（即潮湿）和对流层上冷风（即干燥）的西风导致的陡峭的温度下降速率，是由于中空西风以向西低谷的形式向南穿透，促进了对流不稳定性的形成。向上。与对流不稳定的大气有关的上升气流通过快速收集过冷的水滴而促进了冰晶的生长。这最终通过微物理机制（例如，边缘化过程）导致了gra /冰雹的形成。通过高分辨率数值模型进一步检验了该假设。实验指出，在对流层中和上层，混合相水汽主要存在，并与潜热的释放有关，从而进一步增强了深对流云（即不稳定性）。云的微物理过程的时间演变表明，gra /冰雹占主导地位，这与雨水，云冰和雪的形成是一致的。