Generalized estimates of probable maximum precipitation have been available for the United States east of the 105th meridian for several years. The need for similar data for the planning and design requirements of the Soil Conservation Service in the region west of the 105th meridian led that agency to cooperate with estimates for that area. This report presents generalized estimates of probable maximum precipitation for areas from a point to 400 square miles and for durations up to 24 hours.

The purpose of this publication is to place in the hands of the user derived estimates of some statistical parameters of wind distributions over the Northern Hemisphere. Some of the uses of these derived parameters are discussed in the referenced papers and therefore are not repeated here.