Analysis on an Easterly Wave Thunderstorm and Gale Weather in Latter Flood Season of 2010

[Objective] The research aimed to analyze an easterly wave thunderstorm and gale weather in latter flood season of 2010.[Method] Based on conventional observation data,data of automatic station,NCEP 1°×1° reanalysis data,Doppler radar reflectivity and radial velocity data,the easterly wave thunderstorm and gale weather process which happened during 4-5 August,2010 was analyzed.The circulation situation,wind field and dynamic thermal structures of easterly wave,echo characteristics of Doppler radar when thunderstorm and gale happened were studied.[Result] The thunderstorm and gale weather happened in northeaster zone in front of deep easterly wave trough.When the thunderstorm and gale weather happened,the position of subtropical high was by north(the ridge line was at 35° N).The eastward movement of north branch of trough compelled subtropical high splitting into east and west circulation.The westward extension of east subtropical high and saddle-type filed circulation were favorable for generation and development of easterly wave.As the development and westward movement of easterly wave,in the influence zone in front of trough,the upper easterly component transmitted downward.Then,the low-level northeaster obviously strengthened,and the thunderstorm and gale weather appeared.In the zone where the thunderstorm and gale happened,the airflow at middle and low layers had cyclonic convergence,and had anti-cyclonic divergence near ground layer.The subsidence movement was obvious.Moreover,the thermal structure that it tended to be dry and cold at middle and high layers,warm and wet at low layer existed.The supercell storm was at developed stage on 4th.It had obvious meso-cyclone and hooked echo characteristics(meso-and small-scale characteristics).The characteristics of squall line,gale region and adverse wind region appeared in central west Guangdong on 5th.Doppler characteristics of meso-cyclone,hooked echo,squall line,gale region and adverse wind region had indication significance for the short-imminent forecast of thunderstorm and gale.[Conclusion] The research revealed some information which had significance for forecasting local easterly wave thunderstorm and gale weather.