An operational medium range local weather forecasting system developed in India

A forecasting system for objective medium range location specific forecasts of surface weather elements was evolved at the National Centre for Medium Range Weather Forecasting (NCMRWF). The basic information used for this is the output from a general circulation model (GCM). The two essential compon ents of the system are statistical interpretation (SI) forecast and direct model output (DMO) forecast. These are explained in brief. The SI forecast is obtained by using dynamical-statistical methods like model output statis tics (MOS) and the perfect prog method (PPM) in which prediction of upper a ir circulation from a GCM around the location of interest is used. The DMO forecast is obtained from the prediction of surface weather elements from t he GCM. The procedure for preparation of final forecast by using these two components and prevailing synoptic conditions is also explained. This is es sentially a man-machine-mix approach. Finally, an evaluation of the forecas t skill for the 1996 monsoon and some of the future plans are presented. Co pyright (C) 2000 Royal Meteorological Society.