An adaptation of Shuman and Hovermale's (1968) hemispheric six-layer primitive equations numerical weather prediction model. It used a finer horizontal grid mesh (190. 5 km) to reduce truncation error and was integrated over a subhemispheric domain that permitted a shorter wait (1 h) for the acquisition of observational data. When combined with the use of model output statistics (MOS), the LFM provided a reliable and timely set of guidance products for operational weather forecasts in the United States from 1975 until 1993.