A Generalized Study of Precipitation Forecasting Part 1 : Computation of Precipitation from the Fields of Moisture and Wind

For the eventual purpose of developing a generalized method for predicting precipitation from assumed accurate prognoses of the required meteorological element,s, a preliminary investigation is made of the contemporary relntionship between precipitation and the fields of moisture and wind in the atmosphere. Procedures are developed for calculating the rate of precipitation by computing the divergence of the horizontal wind a t 50-mb. intervals from the surface to 300 mb. using a technique suggested by BelIamy. From these values, vertical speeds are determined. Using the vertical speeds in Fulks’ formula for the rate of precipitation from pseudo-adiabat*ically ascending air, but with some modifications to compensate for non-saturated initial conditions, a method is derived for calculating the intensity of precipitation. Computed amounts are compared with observed precipitation.