Microphysical Structures of Early-Winter Snow Clouds during a Cold Air Outbreak of December 23-25, 2010

A series of videosondes that were continuously launched revealed the microphysical structures of snow clouds during the entire period of an intense cold air outbreak that occurred during December 23-25, 2010. The evolution of the microphysical features of graupel and snowflakes associated with the cold air outbreak were examined. It was found that the precipitation particle distributions in the snow clouds varied as the development of the cold air outbreak progressed. Graupel was the predominant precipitation particle throughout the cold air outbreak, while the number of snowflakes was increasing in the latter half of the period. When the lightning activity was relatively weak, high concentrations of graupel were located at lower level warmer than -10 degrees C. It is suggested that lightning activity is associated with the vertical distribution of graupel.