In this paper an objective analysis scheme using a three-dimensional numerical variational technique has been developed over India and the surrounding region based on the assumption of quasi-geostrophic and thermal wind conditions. Analyses of height, wind and temperature fields at different pressure levels have been made for the depression case which is formed over the Bay of Bengal during the period 26 tb 31 July 1991. The analysis scheme is able to capture the system and to bring out the importance of upper tropospheric warming before the formation of the monsoon depression
