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1. CCN concentration at 0.5% supersaturation best describes the maximum cloud droplet concentration at the cloud bases of the deep convective clouds that developed on the case study days. 2. The concentration of hydrophobic particles that are inefficient CCN is very low. 3. Two clusters of CCN spectra are observed with most of those in the lower concentration cluster corresponding to flights conducted towards the end of the study. 4. The mean ratio of the CCN at 0.5% supersaturation divided by the maximum cloud droplet concentration is equal to 1.24. 5. A strong correlation (R=0.81) is found between the maximum cloud base droplet concentration (in the first 300m of cloud depth) and the CCN concentration at 0.5% supersaturation. 6. 16 case days had cloud droplet effective diameter vs. cloud depth data points with a correlation coefficient greater than 0.85 for each day. 7. Clouds with relatively small cloud base concentrations have 20m cloud droplets closer to the cloud base then those with higher cloud base droplet concentrations. 8. 24m cloud droplet effective diameter is measured only on the cases Sep 21, Sep 23 and Sep 24. On the Sep 16 cases, the cloud droplet distribution was so narrow and the cloud droplet effective diameter so small, that the 16m cloud droplet effective diameter was not measured. 9. Precipitation develops earlier in convective clouds with 20m diameter cloud droplet formation level closer to the cloud bases. 10. Convective clouds with low cloud base droplet concentrations develop precipitation earlier than clouds with high droplet concentrations. 11. Cases with low CCN counts precipitate at a shallower cloud depth. Cases with higher CCN counts developed precipitation at a much higher cloud depth. Conclusions 1. An analysis of the population and composition of aerosols by the TAMU shows that most TDMA hygroscopicity distributions were monomodal, which is consistent with internally-mixed aerosols. Although there was some variability in the aerosol hygroscopicity from flight to flight, most distributions were centered at a growth factor comparable to that of pure ammonium sulfate or bisulfate (Growth Factor ~1.6).The variability in hygroscopicity is reflected in a shift in the corresponding CCN spectrum to the right (decreased hygroscopicity) or the left (increased hygroscopicity). Because of the narrow range in hygroscopicity, the calculated CCN concentration is more strongly dependent upon the measured size distribution than the measured hygroscopicity. In contrast to what is typically observed closer to emissions sources, the concentration of hydrophobic particles that would be inefficient CCN was very low. In fact, none of the hygroscopicity distributions shown in section 4.4 contain a discernable mode centered at a growth factor near 1. Good agreement is observed between the TDMA predicted CCN concentrations and the measured CCN at 0.5% supersaturation. 2. The CCN at 0.5% supersaturation are strongly correlated (R=0.81) to the maximum cloud base droplet concentration in the first 300m of cloud depth. 3. A unique observation is made on the development of cloud droplet effective diameter with cloud depth. On case days with high CCN, the cloud base droplet concentration is relatively high and the cloud droplet effective diameter spectra have a narrow drop size distribution. This is manifested by the 16 case days that had cloud droplet effective diameter vs. cloud depth data points with a correlation coefficient greater than 0.85 for each day. The relationship of the effective diameter with the cloud depth can be characterized mathematically. The effective diameter increases with the cube root of the cloud depth. This unique relationship is very robust and does not vary with the age of the convective cloud or with affects from environmental mixing. 4. A unique relationship is observed between the cloud droplet effective diameter exceeding 20m and the formation of the first precipitation hydrometeors in the updraft stages of convective development. 4