Fluxes of momentum, latent heat and sensible heat at fixed stations in the east-central Arabian sea during MONEX were studied. Observations at the same locations at different periods as well as simultaneous observation at different locations were compared. During the advance of monsoon, momentum flux showed remarkable increase. Latent heat loss from sea also increased while sensible heat flux, in general, changed direction to become a gain by the sea. SST decreased by about 1.5°C and air temperature decreased by about 1°C during the advance phase. A north-south difference in SST in the study region seemed to be favourable for the genesis of onset vortex of monsoon. The possible differential effect of this storm at two different locations, depending upon the SST before the storm, is also discussed.