北京冰雹、雷雨、大风为何总是“组团”来？冰雹为何总在夜间来

Group 1 - The article discusses the recent occurrence of severe convective weather in Beijing, including hail, thunderstorms, and strong winds, particularly during the transition from spring to summer [1][2] - Meteorological departments attribute these weather patterns to the influence of cold vortex systems, which, combined with moisture in the atmosphere, create unstable atmospheric conditions conducive to the formation of severe weather [1] - The period from May to June is identified as a peak time for hail formation due to warming ground temperatures and the continued influence of cold air aloft, creating favorable conditions for hail development [1] Group 2 - The article explains why hail often occurs at night, highlighting the role of daytime heating and the presence of cold air aloft that creates strong convective activity [2] - During the day, intense solar radiation heats the ground, causing air to rise and form strong updrafts, while at night, surface cooling leads to lower temperatures near the ground, but the cold air aloft remains, resulting in strong convection that can produce hail [2] - The interaction between warm, moist air near the surface and cold air above leads to repeated lifting and collision of water droplets and particles, ultimately resulting in hail formation [2]