With rapidly increasing computer power, it has now become possible to include more sophisticated cloud parameterizations into cloud, mesoscale and global models. This has resulted in a large number of new parameterizations of clouds and cloud characteristics (Chen [1994], Feingold and Heymsfield [1992], Ghan and Easter [1992], Donner [1993], Wang and Chang [1993], Lee et al. [1992], Pielke et al. [1992], Tomoaki [1993], Murakami [1990], Kogan [1991], Raymond and Blyth [1992], Kain and Fritsch [1990], Farley et al. [1992], Blyth and Latham [1991], Verlinde et al. [1990]). Parameterizations such as these will allow for increasingly realistic simulations of cloud processes at a variety of scales. An important aspect of any of these parameterizations is their comparison with observations. Preliminary work on data assimilation into cloud models (Verlinde and Cotton [1993]) shows promise that such techniques will allow reasonably accurate short-term forecasts of clouds in the near future.