Abstract
A synoptic example is here presented in the vicinity of Japan in terms of the analysis based on the theory of isentropic upgliding motion described by J. Bjerknes (1). It is clearly seen that the upgliding motion on the warm side and the downgliding motion on the cold side of the cold front advectively generated by the Siberian High progressively develop, leading to the intensification of the front. It is also revealed how the incipient frontal wave has been characterized by the inception that the eastern portion of the cold front has changed into the warm one.
