Abstract
The problem of forecasting precipitation on the west slope of Colorado is discussed. Synoptic situations which result in precipitation on the west slope of Colorado are described. These lead to the selection of five map types upon which an objective aid for forecasting is based. A number of variables are explored under each type and are combined by graphical correlation techniques to arrive at final forecasting charts. The results and test are summarized in the form of skill scores above chance and percent correct forecasts.