北京等地9月现冰雹是否罕见？中央气象台专家回应

Core Viewpoint - The occurrence of severe convective weather, including hailstorms, in northern China during mid-September is unusual but not abnormal, attributed to the interaction of cold and warm air masses as the seasons transition [3][5][6]. Group 1: Weather Phenomena - Severe convective weather, including thunderstorms and hail, was reported in Beijing and surrounding areas due to the influence of a "supercell storm" [1][3]. - The Central Meteorological Observatory issued a blue alert for severe convective weather, predicting continued thunderstorms and hail in various regions [1][3]. - The phenomenon of hail is linked to the characteristics of the thunderstorm clouds, with the size and quantity of hail being influenced by the vertical motion within these clouds [6]. Group 2: Meteorological Analysis - The primary causes of the recent severe weather include the southward movement of the westerly wind belt and the influx of warm, moist air from the south, creating conditions favorable for severe convective weather [3][5]. - Although the frequency of such weather events in September is low, it is not considered rare, as similar occurrences have been documented in previous years [4][5]. - The distribution of hail is uneven, with localized areas experiencing significant accumulation while others remain unaffected, due to the small scale of the thunderstorm clouds [6]. Group 3: Future Weather Predictions - The likelihood of further severe convective weather events is expected to decrease as the transition from summer to autumn progresses, although isolated incidents may still occur [7]. - Predictions indicate potential thunderstorms in specific regions, but the overall probability of severe weather is lower compared to the recent events [7].