Investigation into Supercell Storm on 29 April 2004 in Changde

Utilizing the Changsha and Changde Doppler weather radars data and other conventional meteorological data,the supercell storm occurred on 29 April 2004 associated with 10cm-diameter hail in Anxian town of Hunan has been analyzed.The supercell storm took place in the intersection of a southwest upper-level-jet and a south-southwest low-level jet,where strong thermal potential instability and vertical wind shear favored the genesis of supercell.The supercell storm had a classical hook-shape echo at its right rear extending from the low level upwards to 6km-height,and also a TBSS(three-body scattering spike) indicative of large hails.In the mature stage of the supercell storm the mesocyclone was very strong with a maximum rotational velocity of 24m·s-1 and a vertical vorticity of 1.6×10-2s-1.The vertical section of reflectivity factors reveals that the supercell storm had a large BWER extending over 10km in the horizontal and 4km in the vertical.Above the BWER,there was a reflectivity core region over 70dBZ centered at 9km.This is a structure of classical strong supercell storm.The supercell storm underwent three splittings during the whole evolution.