Improving precipitation forecasts over Iran using a weighted average ensemble technique

In this study, the forecast data are the accumulated 24 hours precipitation forecasts generated by the WRF model. Initialization time is 12 UTC during the period from 1st September of 2011 through 26th February of 2012. The initial conditions for forecasts are provided by the Global Forecast System (GFS) forecasts with 1- degree horizontal resolution. WRF is run with two nested domains. The large domain has a 45 km and the small domain has a 15 The small domain has a horizontal resolution of 15 horizontal resolution. Observational data used in this study consist of the cumulative precipitation observations measured at 0600 UTC in 306 irregularly spaced synoptic meteorological stations spread across Iran. To assess the performance of the ENSWM method, the data are divided into two sets of training and test period. The training period starts from September 1st through November 30th of 2011, and the test period include all the days between December 1st of 2011 and February 26th of 2012. The ensemble forecasts are generated using different configurations of the WRF model. Nine different configurations for the WRF model are used to build members of the system of consciousness.