This paper investigates a case of convective snow that was observed with an occluded-type cyclone. Cross-section and plan-view analyses show that convection resulted from the release of elevated, potential instability by isentropic uplift associated with an easterly trowal airstream (a western extension of the warm conveyor belt) located between 700 and 850 hPa. Forcing for ascent was supplied by low-level frontogenesis, as well as an intensifying 500hPa tropopause fold and its associated potential vorticity anomaly. The latter not only provided a source of very cold, dense air, but also was responsible for lower tropospheric cyclogenesis and subsequent trowal generation.