This study focuses on the initiation and organization of convection anomalies associated with the Madden-Julian oscillation (MJO). Radiosonde data from the Comprehensive Aerological Reference Dataset are used to examine the transition from the dry to the wet phase of the MJO for a set of stations in the Indian Ocean, Maritime Continent, and Western Pacific Ocean. Time series of key dynamical variables and quantities related to the thermal structure of the atmosphere are constructed. Particular attention is paid to the role of the convective available potential energy and the vertical wind shear in the onset and organization of deep convection in the wet phase of the MJO. Factors which consistently precede organization are identified, and the results are used to determine whether wave-CISK or forcing-response is the more appropriate theory for the describing the interaction of convection and the large-scale circulation in the MJO. Differences in the onset of convection over the Maritime continent and the ocean are examined to shed light on why the strength of the convection anomaly diminishes as it moves over the Maritime Continent