Observation analysis of a supercell storm event in the northwest of Hubei Province

Based on data from routine upper-air and surface observations, regional automatic weather stations and Doppler weather radar, we have analyzed the environmental conditions and radar echo characteristics of the supercell in a severe convective weather event occurred in the northwest of Hubei Province on 7 June 2016. The result shows that (1) unstable stratification with dry air in the high and humid air in the low levels, moderate convective available potential energy and medium-weak vertical wind shear are advantageous to the formation of a supercell. Surface mesoscale convergence line and the terrain over northwest Hubei play a key role in triggering the supercell. (2) Factors, such as wide bounded weak echo region and strong overhanging echoes on it, strong inflow in the weak echo region and middle radial convergence (MARC), all indicate that the supercell has a hailfall potential. (3) The interaction of gale nucleus (27 m·s^-1) lasted for more than 2 h, deep mesocyclone with a long life cycle, gust front, downward transport of strong cold advection at upper air and downdrafts in the interior of storm leads to the surface gale. (4) Strong and long slanting updrafts in V-front inflow notch area and the continuance of divergence about storm top result in strong precipitation.