"November 1957." Punched for inclusion in three-ring binder. Includes bibliographical references.

Introduction. pp. 1. Georgraphic and seasonal considerations. pp. 1. Physical nature of the snow vs. rain problem. pp. 5. General synoptic considerations. pp. 8. Forecasting techniques and aids. pp. 10. Methods based on synoptic flow patterns. pp. 11. Methods employing local thermal parameters. pp. 21. An example of application of snow vs. rain forecasting. pp. 26. References. pp. 28. This guide is concerned with the forecasting of snow vs. rain, assuming that precipitation can be correctly predicted. This paper surveys research and forecasting techniques which bear directly upon the snow-rain problem in the United States. Two general approaches have been used; 1. synoptic circulation patterns and 2. thermal relationships (i.e., the use of temperatures at the surface and aloft in separating cases of rain from those of snow). The relative merits of the two basic approaches and of the various methods will be pointed out.