The structure of frontal thunderstorm in winter time is different from that of in summer time over the Korean peninsula, due to dry tongue and upward motion. The dry tongue, that is propagation of dry zone from upper level to lower level, was formed after front passage and the upward motion is intensified by the strengthened low level jet. Since this mechanism makes the structure more unstable, thunderstorm occurs at relatively low cloud top height. This study suggests a forecast guidance of winter time frontal thunderstorm that thunderstorms develop when one of the following conditions are satisfied: 1) total totals (TT) >40, 2) K index >-10, 3) mixing ratio ${geq}$ 3.5 g/kg.