Verification of WRF Precipitation Forecast Over Iran Country During Nov. 2008-Jun. 2009

This study presents verification of the Weather Research and Forecasting (WRF) model for the 24-h accumulated precipitation forecasts in Iran for the period of November 2008 to June 2009 for 24, 48, and 72.houre-ranges. Verification is done separately for three precipitation ranges and nine different regions in the country via 2×2 contingency table and quantities attributed to it. Though precipitation is the most difficult parameter to forecast, results show the good skill of WRF Forecasts.However regarding the bias, the model has over-forecasting. In northern parts of Iran with the highest rainfall rate, the value of TS is more than 0.50 and shows the highest accuracy of precipitation forecasts in different regions. In the regions with the lowest rainfall rates (east and southeast of Iran) TS is less than 0.40 and the model results show the least accuracy. Economic value of the forecasts reaches 60% for the cost to loss ratios of less than 0.40. This recommends the operational use of this model.