Abstract:By using convensional observation data, Doppler radar data and NCEP 1°×1° reanalysis data, the water vapor condition, unstable energy, triggering mechanism and radar echo characteristics of a snowstorm process accompanied with thunderstorm during 28 February -1 March,2010 in Jinan, Shandong province were combined to diagnostically analyze the convection process. Results show that: (1) The snowstorm was caused by upper-level trough; warm and moist jets at 700 hPa or low level were able to provide sufficient water vapor to snowstorm region. (2) The potential convection instability and conditional symmetric instability caused the thunder to take place in the snowstorm. However, it was the frontogenetical secondary circulation that initiated the convection. (3) The band echoes and strong vertical wind shear of Doppler radar products reflected the existence of conditional symmetric instability. The cloud top, higher than -40℃ level, was necessary to lightning production.