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<br />7 <br /> <br />particle to spend a sufficient time in the cloud under favorable growth conditions. <br /> <br />b. December 9th <br /> <br />The clouds on this day were post-frontal, with embedded convection in a <br />stratiform orographic cloud. In the upper levels of this cloud, dendrites and aggregates of <br />dendrites were developing (Fig. 1O).1n convective regions of the clouds, the coalescence <br />process followed in many cases by drop freezing and growth to graupel by riming <br />dominated the precipitation process, (Fig. 11)as discussed above. In literature this <br />mechanism has been called the CRG (coalescence-riming-graupel) process <br />(Silverman,1986; Braham,1986). <br />An example of a region with the CRG mechanism active is shown in figure 12. <br />These data were collected just upwind of the mountains in embedded convection. High <br />liquid water contents were encountered at the -10 C level in regions of 4 to 6 ms-l <br />updraft. The 2D-C images in this region show the presence of large drops up to 800 <br />microns diameter (Figure 12). The model calculations presented above show that growth <br />of the tail of the cloud droplet distribution by direct: coalescence with other cloud droplets <br />can account for the observed panicles at this level. <br />Figure 13 presents data collected during a penetration through a typical region of <br />embedded convection, with aggregates of dendrites and stellars in the non-convective <br />portions of the penetration, and more spherical graupel particles in the convective <br />portions. <br /> <br />4. DISCUSSION <br /> <br />The clouds observed with the UND aircraft on December 8 and 9, 1985 representia fairly typical winter storm event in Morocco. These types of storm systems lead to <br />