The transformation of the cP air mass into the mP air mass due to upward heat and moisture supplies from the warmer sea surface around Japan is investigated. Keeping aloof from treating the transfer processes theoretically, available measured data are utilized for evaluating the modification processes and constructing a lower atmospheric cross section following the air column throughout the whole modified layers. The results are almost the same as those of former investigations¹⁾ obtained theoretically with little addition to be made. But this report will serve to verify those result with the actually observed informations and to present some simple clue to the forecasting of the cloud and the snowfall.