We report here new results that further elucidate the role of buoyancy-driven convective flows in determining the distribution of vapor mole fraction and temperature in the thermal diffusion cloud chamber. A two-dimensional model describing both diffusion and convection in the presence of chamber sidewalls is presented. The model equations are used to analyze 1-butanol and 1-pentanol nucleation data obtained earlier. The results of the investigation show that convective flow is nearly always present and, in the cases considered here, result in a reduction in the value of the calculated critical supersaturation (as compared to the one-dimensional case). The dependence of critical supersaturation with total pressure reported earlier is smaller but is not eliminated.