Convective activities tend to substantially increase over the Korean Peninsula after a rainfall zone associated with a quasi-stationary front over East Asia disappears in the end of July. This period is coincident with the expansion of the North Pacific High that brings in more unstable atmosphere over the Korean Peninsula. For the prediction of severe storms during the summer time, we developed a physical method for estimating stability indices from MODIS infrared measurements using a one-dimensional data assimilation approach. In order to obtain atmospheric profiles assimilated to MODIS measurements, the first guessed atmospheric profiles from Regional Data Assimilation and Prediction System (RDAPS) data produced by Korea Meteorological Administration (KMA) were updated by iteration processes in which a system simulating the brightness temperature is imbedded. The estimated stability indices were compared with those from ground observations. It was shown that stability indices from MODIS brightness temperature measurements can be used to identify the potential storm-developing area.