The Combined Role of Kinematics, Thermodynamics and Cloud Physics Associated with Heavy Snowfall Episodes

Abstract

A winter cyclone of average size, but strong intensity, was analyzed in detail to ascertain its kinematic features of a level of nondivergence at 550mb (-16°C) with upward vertical velocities of 6.5 cm sec -1. Calculations of a water balance were also made indicating a precipitation efficiency of approximately 80%. It was found that regions of maximum rate of condensate that occur near the level of nondivergence at temperature regimes near -15°C must be suspect for producing heavy snowfall episodes. This finding was collaborated by a mini-climatological study of 75 heavy snowfall episodes which depicted saturated ascent through the level of nondivergence at θe=304-309°K (i.e., 600-mb temperature of -13-15°C).