一次强雷电大暴雨天气系统分析及预报探讨

Analysis and Forecast of a Strong Thunder and Rainstorm Weather

2007年8月28日凌晨,江苏省淮安市出现了区域性强雷电和大暴雨天气,其中在28日02:12～08:10市区及周边部分县区出现了连续性强雷电天气。通过对高低空实况天气图分析发现:8月27日20:00500、700、850hPa图上,在28°～35°N、115°～121°E范围内均为气旋辐合区,整个淮安市均位于辐合区内东北部,地面有低涡相配合,特别是500hPa辐合区出现在副热带高压内,更加重了辐合区内的不稳定能量。深厚的气旋辐合系统和较强的不稳定能量,是造成8月28日02:12～08:10持续性强雷电和大暴雨的重要因素。而8月26日20:00ECMWF产品对8月27日20:00环流形势预报效果较好,能提早20h左右获得较准确的预报依据,便于在短期时效内开展预报服务工作。

Consecutive strong thunder and rainstorm weather appeared in the downtown and surrounding counties and districts of Huaian from 2：12 to 8：10 on August 28,2007.As indicated by the analysis on the high and low-altitude weather map,on the 500,700 and 850 hPa live map at 20：00 on August 27,there were cyclone convergence areas around 28-35°N and 115-121°E,Huaian was located in the northeastern part of the convergence area with the low vortex on ground to coordinate,the appearance of 500 hPa convergence area in the subtropical high area aggravated the instability energy in the convergence area.The deep cyclone convergence system and the strong instability energy were the important factors contributing the long-enduring strong thunder and rainstorm from 02：12 to 08：10 on August 28.And the ECMWF products at 20：00 on August 26 was effective to forecast the circulation situation at 20：00 on August 27,to advance about 20 hours could obtain the accurate forecast basis,so as to forecast in the short-term.