摘要 2019年3月21日21：13（北京时），广西桂林市临桂区国家气象观测站录到60.3 m ·s-1极端大风，打破了广西气象站建站以来的历史极值。综合利用多种观测资料对临桂极端大风的发展演变和成因进行详细分析，结果表明：（1）地面锋前暖区对流在移近临桂站时地面冷空气的适时入侵促进其发展成超级单体风暴，其产生的下击暴流击中临桂测站造成极端大风。（2）雷达回波表明该超级单体具有明显的钩状回波、中层径向辐合、近地面强辐散及反射率因子核心下降等雷达特征；风暴垂直方向流场结构表现为上面是反气旋性旋转或辐合、中间为径向速度辐合、底下为气旋性旋转。（3）中层径向辐合加强导致中气旋旋转性加大、直径减小、厚度增加，近地面层的强中气旋对下击暴流有加强作用。（4）环境条件分析表明临桂上空具有极好的产生雷暴大风的环境条件和发展成超级单体风暴的潜势。（5）极端雨强与极端大风相伴出现，表明降水拖曳作用是极端大风产生原因之一；在地形作用下冷空气大风对极端大风形成有叠加效应。
Extreme gale of 60.3 m·s-1 was recorded by the national meteorological observation station at Lingui in Guangxi at 21:13 BT 21 March 2019, breaking the historical extreme value since the establishment of Guangxi meteorological stations. In this study, the development and formation of the extreme wind event were analyzed in detail by using a variety of observation data. The analysis indicates the following results. (1) The strong wind occurred at Lingui station was caused by a downburst introduced by a supercell storm, which is originated from convection in the warm zone before the cold front, and developed while meeting with cold air timely near the Lingui station. (2) Radar echoes show that the supercell has obvious radar characteristics such as hook echo, Mid-altitude Radial Convergence (MARC), strong divergence near the ground and decrease of reflectivity factor core. The flow field structure in the vertical direction of the storm reveals anticyclonic rotation or convergence at the top, MARC at the middle and cyclonic rotation at the bottom. (3) The strengthening of MARC led to the intensifying of rotation of the mesocyclone, the decrease of its diameter and the increase of its thickness. Especially, the strong mesocyclone near the ground level strengthens the downburst. (4) The environmental conditions indicated that there are excellent environmental conditions for producing thunderstorm gale and the potential of developing supercell storm over Lingui station. (5) The extreme precipitation had a drag effect on the gale. Under the action of topography, cold air wind has superimposed effect on extreme wind.