Some Characteristics of the MOS POP System in the WSFO Washington D.C. Forecast Area for the Cool Season

Model Output Statistics (MOS) forecasts of the Probability of Precipitation (POP) are currently provided twice daily based on the Limited-area Fine Mesh (LFM) model (National Weather Service, 1980). The regional approach was used to develop the POP equations. In the regional approach data are combined from a number of stations within a region to develop regression equations for that region. This approach helps to minimize the deterioration of forecast accuracy on independent data samples and is used when the size of the sample will not support the development of equations for each station.